From 3f44c6538d635967af55aa3ad0bebccb0b5f953c Mon Sep 17 00:00:00 2001
From: Igor Wojda <igor.wojda@gmail.com>
Date: Tue, 7 Feb 2023 19:33:40 +0100
Subject: [PATCH] Rename files (#97)

---
 .test/README.md                               |   4 +-
 .../challenge/utils/ChallengeFile.kt          |   6 +-
 .../challenge/utils/ChallengeFile.kt          |   6 +-
 README.md                                     |   6 +-
 misc/ChallengeGroups.md                       | 206 +++++++++---------
 .../challenge/{challenge.kt => Challenge.kt}  |   0
 .../challenge/{readme.md => README.md}        |   2 +-
 .../challenge/{solution.kt => Solution.kt}    |   0
 .../addupto/{challenge.kt => Challenge.kt}    |   0
 .../integer/addupto/{readme.md => README.md}  |   2 +-
 .../addupto/{solution.kt => Solution.kt}      |   0
 .../countdown/{challenge.kt => Challenge.kt}  |   0
 .../countdown/{readme.md => README.md}        |   2 +-
 .../countdown/{solution.kt => Solution.kt}    |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../countupanddown/{readme.md => README.md}   |   4 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../digitfrequency/{readme.md => README.md}   |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../factorial/{challenge.kt => Challenge.kt}  |   0
 .../factorial/{readme.md => README.md}        |   2 +-
 .../factorial/{solution.kt => Solution.kt}    |   0
 .../basic/{challenge.kt => Challenge.kt}      |   0
 .../fibonacci/basic/{readme.md => README.md}  |   0
 .../basic/{solution.kt => Solution.kt}        |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../recursivecached/{readme.md => README.md}  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../fizzbuzz/{challenge.kt => Challenge.kt}   |   0
 .../integer/fizzbuzz/{readme.md => README.md} |   2 +-
 .../fizzbuzz/{solution.kt => Solution.kt}     |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../generateallpairs/{readme.md => README.md} |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../getodd/{challenge.kt => Challenge.kt}     |   0
 .../integer/getodd/{readme.md => README.md}   |   4 +-
 .../getodd/{solution.kt => Solution.kt}       |   0
 .../power/{challenge.kt => Challenge.kt}      |   0
 .../integer/power/{readme.md => README.md}    |   2 +-
 .../power/{solution.kt => Solution.kt}        |   0
 .../basic/{challenge.kt => Challenge.kt}      |   0
 .../basic/{readme.md => README.md}            |   2 +-
 .../basic/{solution.kt => Solution.kt}        |   0
 .../steps/{challenge.kt => Challenge.kt}      |   0
 .../steps/{readme.md => README.md}            |   2 +-
 .../steps/{solution.kt => Solution.kt}        |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../pyramidgenerator/{readme.md => README.md} |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../reverse/{challenge.kt => Challenge.kt}    |   0
 .../integer/reverse/{readme.md => README.md}  |   2 +-
 .../reverse/{solution.kt => Solution.kt}      |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../stepsgenerator/{readme.md => README.md}   |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../base/{challenge.kt => Challenge.kt}       |   0
 .../doubly/base/{readme.md => README.md}      |   4 +-
 .../doubly/base/{solution.kt => Solution.kt}  |   0
 .../base/{challenge.kt => Challenge.kt}       |   0
 .../singly/base/{readme.md => README.md}      |   2 +-
 .../singly/base/{solution.kt => Solution.kt}  |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../circularcheck/{readme.md => README.md}    |   4 +-
 .../{solution.kt => Solution.kt}              |   0
 .../fromlast/{challenge.kt => Challenge.kt}   |   0
 .../singly/fromlast/{readme.md => README.md}  |   8 +-
 .../fromlast/{solution.kt => Solution.kt}     |   0
 .../midpoint/{challenge.kt => Challenge.kt}   |   0
 .../singly/midpoint/{readme.md => README.md}  |   2 +-
 .../midpoint/{solution.kt => Solution.kt}     |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../capitalizeFirst/{readme.md => README.md}  |   4 +-
 .../{solution.kt => Solution.kt}              |   0
 .../list/coins/{challenge.kt => Challenge.kt} |   0
 .../list/coins/{readme.md => README.md}       |   2 +-
 .../list/coins/{solution.kt => Solution.kt}   |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../flatten/{challenge.kt => Challenge.kt}    |   0
 .../list/flatten/{readme.md => README.md}     |   4 +-
 .../list/flatten/{solution.kt => Solution.kt} |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../formattrainroute/{readme.md => README.md} |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../listchunk/{challenge.kt => Challenge.kt}  |   0
 .../list/listchunk/{readme.md => README.md}   |   2 +-
 .../listchunk/{solution.kt => Solution.kt}    |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../maxsublistsum/{readme.md => README.md}    |   4 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../minsublistlength/{readme.md => README.md} |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../list/pairaverage/{readme.md => README.md} |   2 +-
 .../pairaverage/{solution.kt => Solution.kt}  |   0
 .../product/{challenge.kt => Challenge.kt}    |   0
 .../list/product/{readme.md => README.md}     |   2 +-
 .../list/product/{solution.kt => Solution.kt} |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../binarysearch/{readme.md => README.md}     |   2 +-
 .../binarysearch/{solution.kt => Solution.kt} |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../linearsearch/{readme.md => README.md}     |   2 +-
 .../linearsearch/{solution.kt => Solution.kt} |   0
 .../bubblesort/{challenge.kt => Challenge.kt} |   0
 .../sort/bubblesort/{readme.md => README.md}  |   2 +-
 .../bubblesort/{solution.kt => Solution.kt}   |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../insertionsort/{readme.md => README.md}    |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../mergesort/{challenge.kt => Challenge.kt}  |   0
 .../sort/mergesort/{readme.md => README.md}   |   2 +-
 .../mergesort/{solution.kt => Solution.kt}    |   0
 .../quicksort/{challenge.kt => Challenge.kt}  |   0
 .../sort/quicksort/{readme.md => README.md}   |   2 +-
 .../quicksort/{solution.kt => Solution.kt}    |   0
 .../radixsort/{challenge.kt => Challenge.kt}  |   0
 .../sort/radixsort/{readme.md => README.md}   |   2 +-
 .../radixsort/{solution.kt => Solution.kt}    |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../selectionsort/{readme.md => README.md}    |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../list/squareequal/{readme.md => README.md} |   2 +-
 .../squareequal/{solution.kt => Solution.kt}  |   0
 .../subtract/{challenge.kt => Challenge.kt}   |   0
 .../list/subtract/{readme.md => README.md}    |  12 +-
 .../subtract/{solution.kt => Solution.kt}     |   0
 .../sumzero/{challenge.kt => Challenge.kt}    |   0
 .../list/sumzero/{readme.md => README.md}     |   2 +-
 .../list/sumzero/{solution.kt => Solution.kt} |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../findrectangle/{readme.md => README.md}    |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../basic/{challenge.kt => Challenge.kt}      |   0
 .../queue/basic/{readme.md => README.md}      |   4 +-
 .../queue/basic/{solution.kt => Solution.kt}  |   0
 .../combine/{challenge.kt => Challenge.kt}    |   0
 .../queue/combine/{readme.md => README.md}    |   2 +-
 .../combine/{solution.kt => Solution.kt}      |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../containsrange/{readme.md => README.md}    |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../basic/{challenge.kt => Challenge.kt}      |   0
 .../stack/basic/{readme.md => README.md}      |   2 +-
 .../stack/basic/{solution.kt => Solution.kt}  |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../caesarcipher/{readme.md => README.md}     |   2 +-
 .../caesarcipher/{solution.kt => Solution.kt} |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../{readme.md => README.md}                  |   4 +-
 .../{solution.kt => Solution.kt}              |   0
 .../isanagram/{challenge.kt => Challenge.kt}  |   0
 .../string/isanagram/{readme.md => README.md} |   2 +-
 .../isanagram/{solution.kt => Solution.kt}    |   0
 .../basic/{challenge.kt => Challenge.kt}      |   0
 .../basic/{readme.md => README.md}            |   2 +-
 .../basic/{solution.kt => Solution.kt}        |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../permutation/{readme.md => README.md}      |   4 +-
 .../permutation/{solution.kt => Solution.kt}  |   0
 .../tolerant/{challenge.kt => Challenge.kt}   |   0
 .../tolerant/{readme.md => README.md}         |   4 +-
 .../tolerant/{solution.kt => Solution.kt}     |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../issubstring/{readme.md => README.md}      |   2 +-
 .../issubstring/{solution.kt => Solution.kt}  |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../longestword/{readme.md => README.md}      |   2 +-
 .../longestword/{solution.kt => Solution.kt}  |   0
 .../maxchar/{challenge.kt => Challenge.kt}    |   0
 .../string/maxchar/{readme.md => README.md}   |   4 +-
 .../maxchar/{solution.kt => Solution.kt}      |   0
 .../reverse/{challenge.kt => Challenge.kt}    |   0
 .../string/reverse/{readme.md => README.md}   |   2 +-
 .../reverse/{solution.kt => Solution.kt}      |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../surroundedletter/{readme.md => README.md} |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../vowels/{challenge.kt => Challenge.kt}     |   0
 .../string/vowels/{readme.md => README.md}    |   2 +-
 .../vowels/{solution.kt => Solution.kt}       |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../binarysearchtree/{readme.md => README.md} |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../insert/{challenge.kt => Challenge.kt}     |   0
 .../insert/{readme.md => README.md}           |   2 +-
 .../insert/{solution.kt => Solution.kt}       |   0
 .../validate/{challenge.kt => Challenge.kt}   |   0
 .../validate/{readme.md => README.md}         |   2 +-
 .../validate/{solution.kt => Solution.kt}     |   0
 .../levelwidth/{challenge.kt => Challenge.kt} |   0
 .../levelwidth/{readme.md => README.md}       |   4 +-
 .../levelwidth/{solution.kt => Solution.kt}   |   0
 .../traversal/{challenge.kt => Challenge.kt}  |   0
 .../traversal/{readme.md => README.md}        |   2 +-
 .../traversal/{solution.kt => Solution.kt}    |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../maxbinaryheap/{readme.md => README.md}    |   2 +-
 .../{solution.kt => Solution.kt}              |   0
 .../{challenge.kt => Challenge.kt}            |   0
 .../anycallback/{readme.md => README.md}      |   6 +-
 .../anycallback/{solution.kt => Solution.kt}  |   0
 221 files changed, 208 insertions(+), 208 deletions(-)
 rename misc/template/challenge/{challenge.kt => Challenge.kt} (100%)
 rename misc/template/challenge/{readme.md => README.md} (83%)
 rename misc/template/challenge/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/addupto/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/addupto/{readme.md => README.md} (81%)
 rename src/test/kotlin/com/igorwojda/integer/addupto/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/countdown/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/countdown/{readme.md => README.md} (81%)
 rename src/test/kotlin/com/igorwojda/integer/countdown/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/countupanddown/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/countupanddown/{readme.md => README.md} (76%)
 rename src/test/kotlin/com/igorwojda/integer/countupanddown/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/digitfrequency/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/digitfrequency/{readme.md => README.md} (86%)
 rename src/test/kotlin/com/igorwojda/integer/digitfrequency/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/factorial/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/factorial/{readme.md => README.md} (88%)
 rename src/test/kotlin/com/igorwojda/integer/factorial/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fibonacci/basic/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fibonacci/basic/{readme.md => README.md} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fibonacci/basic/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/{readme.md => README.md} (94%)
 rename src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fizzbuzz/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/fizzbuzz/{readme.md => README.md} (91%)
 rename src/test/kotlin/com/igorwojda/integer/fizzbuzz/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/generateallpairs/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/generateallpairs/{readme.md => README.md} (91%)
 rename src/test/kotlin/com/igorwojda/integer/generateallpairs/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/getodd/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/getodd/{readme.md => README.md} (75%)
 rename src/test/kotlin/com/igorwojda/integer/getodd/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/power/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/power/{readme.md => README.md} (87%)
 rename src/test/kotlin/com/igorwojda/integer/power/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/printnumber/basic/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/printnumber/basic/{readme.md => README.md} (85%)
 rename src/test/kotlin/com/igorwojda/integer/printnumber/basic/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/printnumber/steps/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/printnumber/steps/{readme.md => README.md} (88%)
 rename src/test/kotlin/com/igorwojda/integer/printnumber/steps/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/pyramidgenerator/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/pyramidgenerator/{readme.md => README.md} (89%)
 rename src/test/kotlin/com/igorwojda/integer/pyramidgenerator/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/reverse/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/reverse/{readme.md => README.md} (83%)
 rename src/test/kotlin/com/igorwojda/integer/reverse/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/stepsgenerator/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/integer/stepsgenerator/{readme.md => README.md} (88%)
 rename src/test/kotlin/com/igorwojda/integer/stepsgenerator/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/doubly/base/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/doubly/base/{readme.md => README.md} (98%)
 rename src/test/kotlin/com/igorwojda/linkedlist/doubly/base/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/base/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/base/{readme.md => README.md} (99%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/base/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/{readme.md => README.md} (91%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/{readme.md => README.md} (78%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/{readme.md => README.md} (96%)
 rename src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/capitalizeFirst/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/capitalizeFirst/{readme.md => README.md} (84%)
 rename src/test/kotlin/com/igorwojda/list/capitalizeFirst/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/coins/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/coins/{readme.md => README.md} (87%)
 rename src/test/kotlin/com/igorwojda/list/coins/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/countuniquevalues/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/countuniquevalues/{readme.md => README.md} (83%)
 rename src/test/kotlin/com/igorwojda/list/countuniquevalues/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/flatten/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/flatten/{readme.md => README.md} (91%)
 rename src/test/kotlin/com/igorwojda/list/flatten/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/formattrainroute/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/formattrainroute/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/list/formattrainroute/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/listchunk/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/listchunk/{readme.md => README.md} (89%)
 rename src/test/kotlin/com/igorwojda/list/listchunk/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/maxsublistsum/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/maxsublistsum/{readme.md => README.md} (89%)
 rename src/test/kotlin/com/igorwojda/list/maxsublistsum/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/minsublistlength/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/minsublistlength/{readme.md => README.md} (92%)
 rename src/test/kotlin/com/igorwojda/list/minsublistlength/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/pairaverage/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/pairaverage/{readme.md => README.md} (90%)
 rename src/test/kotlin/com/igorwojda/list/pairaverage/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/product/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/product/{readme.md => README.md} (86%)
 rename src/test/kotlin/com/igorwojda/list/product/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/search/binarysearch/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/search/binarysearch/{readme.md => README.md} (95%)
 rename src/test/kotlin/com/igorwojda/list/search/binarysearch/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/search/linearsearch/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/search/linearsearch/{readme.md => README.md} (89%)
 rename src/test/kotlin/com/igorwojda/list/search/linearsearch/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/bubblesort/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/bubblesort/{readme.md => README.md} (96%)
 rename src/test/kotlin/com/igorwojda/list/sort/bubblesort/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/insertionsort/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/insertionsort/{readme.md => README.md} (89%)
 rename src/test/kotlin/com/igorwojda/list/sort/insertionsort/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/mergesort/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/mergesort/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/list/sort/mergesort/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/quicksort/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/quicksort/{readme.md => README.md} (92%)
 rename src/test/kotlin/com/igorwojda/list/sort/quicksort/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/radixsort/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/radixsort/{readme.md => README.md} (97%)
 rename src/test/kotlin/com/igorwojda/list/sort/radixsort/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/selectionsort/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sort/selectionsort/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/list/sort/selectionsort/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/squareequal/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/squareequal/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/list/squareequal/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/subtract/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/subtract/{readme.md => README.md} (77%)
 rename src/test/kotlin/com/igorwojda/list/subtract/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sumzero/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/list/sumzero/{readme.md => README.md} (88%)
 rename src/test/kotlin/com/igorwojda/list/sumzero/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/matrix/findallrectangles/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/matrix/findallrectangles/{readme.md => README.md} (91%)
 rename src/test/kotlin/com/igorwojda/matrix/findallrectangles/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/matrix/findrectangle/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/matrix/findrectangle/{readme.md => README.md} (94%)
 rename src/test/kotlin/com/igorwojda/matrix/findrectangle/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/{readme.md => README.md} (91%)
 rename src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/queue/basic/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/queue/basic/{readme.md => README.md} (92%)
 rename src/test/kotlin/com/igorwojda/queue/basic/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/queue/combine/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/queue/combine/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/queue/combine/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/range/containsrange/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/range/containsrange/{readme.md => README.md} (84%)
 rename src/test/kotlin/com/igorwojda/range/containsrange/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/stack/basic/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/stack/basic/{readme.md => README.md} (94%)
 rename src/test/kotlin/com/igorwojda/stack/basic/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/caesarcipher/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/caesarcipher/{readme.md => README.md} (92%)
 rename src/test/kotlin/com/igorwojda/string/caesarcipher/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/capitalizesentence/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/capitalizesentence/{readme.md => README.md} (83%)
 rename src/test/kotlin/com/igorwojda/string/capitalizesentence/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/decapitalizeconst/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/decapitalizeconst/{readme.md => README.md} (90%)
 rename src/test/kotlin/com/igorwojda/string/decapitalizeconst/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/getduplicatedarguments/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/getduplicatedarguments/{readme.md => README.md} (90%)
 rename src/test/kotlin/com/igorwojda/string/getduplicatedarguments/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/{readme.md => README.md} (86%)
 rename src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/isanagram/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/isanagram/{readme.md => README.md} (92%)
 rename src/test/kotlin/com/igorwojda/string/isanagram/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/basic/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/basic/{readme.md => README.md} (87%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/basic/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/{readme.md => README.md} (85%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/{readme.md => README.md} (86%)
 rename src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/issubstring/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/issubstring/{readme.md => README.md} (92%)
 rename src/test/kotlin/com/igorwojda/string/issubstring/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/longestword/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/longestword/{readme.md => README.md} (88%)
 rename src/test/kotlin/com/igorwojda/string/longestword/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/maxchar/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/maxchar/{readme.md => README.md} (84%)
 rename src/test/kotlin/com/igorwojda/string/maxchar/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/reverse/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/reverse/{readme.md => README.md} (85%)
 rename src/test/kotlin/com/igorwojda/string/reverse/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/surroundedletter/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/surroundedletter/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/string/surroundedletter/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/vowels/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/string/vowels/{readme.md => README.md} (84%)
 rename src/test/kotlin/com/igorwojda/string/vowels/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/binarysearchtree/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/binarysearchtree/{readme.md => README.md} (87%)
 rename src/test/kotlin/com/igorwojda/tree/binarysearchtree/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/binarytree/insert/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/binarytree/insert/{readme.md => README.md} (95%)
 rename src/test/kotlin/com/igorwojda/tree/binarytree/insert/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/binarytree/validate/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/binarytree/validate/{readme.md => README.md} (94%)
 rename src/test/kotlin/com/igorwojda/tree/binarytree/validate/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/classic/levelwidth/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/classic/levelwidth/{readme.md => README.md} (73%)
 rename src/test/kotlin/com/igorwojda/tree/classic/levelwidth/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/classic/traversal/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/classic/traversal/{readme.md => README.md} (98%)
 rename src/test/kotlin/com/igorwojda/tree/classic/traversal/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/{readme.md => README.md} (93%)
 rename src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/{solution.kt => Solution.kt} (100%)
 rename src/test/kotlin/com/igorwojda/various/anycallback/{challenge.kt => Challenge.kt} (100%)
 rename src/test/kotlin/com/igorwojda/various/anycallback/{readme.md => README.md} (78%)
 rename src/test/kotlin/com/igorwojda/various/anycallback/{solution.kt => Solution.kt} (100%)

diff --git a/.test/README.md b/.test/README.md
index 3a97890b..9cab8d15 100644
--- a/.test/README.md
+++ b/.test/README.md
@@ -6,10 +6,10 @@ This subproject is designed to verify the root project. Checks are running with
 
 Verify correctness of the provided solutions.
 
-Every coding challenge in this repo consists of a container (`challenge.kt` file) that has tests and
+Every coding challenge in this repo consists of a container that has tests and
 empty placeholder for a user-coded solution. Since the placeholder is non-implemented method
 all tests in the root project will fail by design. This subproject allows to generate a test suite for each challenge
-by combining challenge container (`challenge.kt` file) with every solution present in the `solution.kt` file.
+by combining challenge container (`Challenge.kt` file) with every solution present in the `Solution.kt` file.
 
 To generate tests go into `.test` subproject and run the `generateTests` command:
 
diff --git a/.test/buildSrc/src/main/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt b/.test/buildSrc/src/main/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt
index 0d98fe95..1ad5490f 100644
--- a/.test/buildSrc/src/main/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt
+++ b/.test/buildSrc/src/main/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt
@@ -1,7 +1,7 @@
 package com.igorwojda.challenge.utils
 
 enum class ChallengeFile(val fileName: String) {
-    SOLUTIONS_KT("solution.kt"),
-    DESC_MD("readme.md"),
-    CHALLENGE_KT("challenge.kt"),
+    SOLUTIONS_KT("Solution.kt"),
+    DESC_MD("README.md"),
+    CHALLENGE_KT("Challenge.kt"),
 }
diff --git a/.test/src/test/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt b/.test/src/test/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt
index 0d98fe95..1ad5490f 100644
--- a/.test/src/test/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt
+++ b/.test/src/test/kotlin/com/igorwojda/challenge/utils/ChallengeFile.kt
@@ -1,7 +1,7 @@
 package com.igorwojda.challenge.utils
 
 enum class ChallengeFile(val fileName: String) {
-    SOLUTIONS_KT("solution.kt"),
-    DESC_MD("readme.md"),
-    CHALLENGE_KT("challenge.kt"),
+    SOLUTIONS_KT("Solution.kt"),
+    DESC_MD("README.md"),
+    CHALLENGE_KT("Challenge.kt"),
 }
diff --git a/README.md b/README.md
index 572214ed..1940ce1e 100644
--- a/README.md
+++ b/README.md
@@ -12,12 +12,12 @@ help you to become a better programmer and improve your chance of getting a new
 Each challenge is located in separate package, and it contains 3 main
 files ([screen](./misc/image/challenge-structure.png)):
 
-- `readme.md` - the task description.
-- `challenge.kt` - file containing an empty method/class where challenge should be solved. This file also contains
+- `README.md` - the task description.
+- `Challenge.kt` - file containing an empty method/class where challenge should be solved. This file also contains
   set of test and occasionally helper methods. You can run all tests directly from this file (click green arrow next to
   `Test` class).
   [JUnit](https://junit.org/junit4/) tests which verify that task was solved correctly.
-- `solution.kt` - a file containing one or more solutions.
+- `Solution.kt` - a file containing one or more solutions.
 
 Keep in mind that each challenge will usually have more than one solution. Even simple challenges like
 [String reversal](src/test/kotlin/com/igorwojda/string/reverse) can be solved in
diff --git a/misc/ChallengeGroups.md b/misc/ChallengeGroups.md
index f8904932..8c009ce5 100644
--- a/misc/ChallengeGroups.md
+++ b/misc/ChallengeGroups.md
@@ -7,19 +7,19 @@ type of problem (searching, sorting etc.). One challenge may fit int outfile gro
 
 List of problems that can be solved using [recursion](https://en.wikipedia.org/wiki/Recursion_(computer_science)).
 
-- [Count down](../src/test/kotlin/com/igorwojda/integer/countdown/readme.md)
-- [Get odd](../src/test/kotlin/com/igorwojda/integer/getodd/readme.md)
-- [Any callback](../src/test/kotlin/com/igorwojda/various/anycallback/readme.md)
-- [Power](../src/test/kotlin/com/igorwojda/integer/power/readme.md)
-- [Binary search tree (validate)](../src/test/kotlin/com/igorwojda/tree/binarytree/validate/readme.md)
-- [Fibonacci](../src/test/kotlin/com/igorwojda/integer/fibonacci/basic/readme.md)
-- [Fibonacci with recursive cache](../src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/readme.md)
-- [Add up to](../src/test/kotlin/com/igorwojda/integer/addupto/readme.md)
-- [Power](../src/test/kotlin/com/igorwojda/integer/power/readme.md)
-- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/readme.md)
-- [Capitalize first](../src/test/kotlin/com/igorwojda/list/capitalizeFirst/readme.md)
-- [Merge sort](../src/test/kotlin/com/igorwojda/list/sort/mergesort/readme.md)
-- [Quick sort](../src/test/kotlin/com/igorwojda/list/sort/quicksort/readme.md)
+- [Count down](../src/test/kotlin/com/igorwojda/integer/countdown/README.md)
+- [Get odd](../src/test/kotlin/com/igorwojda/integer/getodd/README.md)
+- [Any callback](../src/test/kotlin/com/igorwojda/various/anycallback/README.md)
+- [Power](../src/test/kotlin/com/igorwojda/integer/power/README.md)
+- [Binary search tree (validate)](../src/test/kotlin/com/igorwojda/tree/binarytree/validate/README.md)
+- [Fibonacci](../src/test/kotlin/com/igorwojda/integer/fibonacci/basic/README.md)
+- [Fibonacci with recursive cache](../src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/README.md)
+- [Add up to](../src/test/kotlin/com/igorwojda/integer/addupto/README.md)
+- [Power](../src/test/kotlin/com/igorwojda/integer/power/README.md)
+- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/README.md)
+- [Capitalize first](../src/test/kotlin/com/igorwojda/list/capitalizeFirst/README.md)
+- [Merge sort](../src/test/kotlin/com/igorwojda/list/sort/mergesort/README.md)
+- [Quick sort](../src/test/kotlin/com/igorwojda/list/sort/quicksort/README.md)
   
 ### Recursion with helper function 
 
@@ -27,154 +27,154 @@ Recurrent helper function is useful when we want to solve problem in recursive w
 API by changing method signature of the original method eg. we don't want to add new parameters (additional data required
 for recursive call) or change return type (eg. change `List<Int>` to `MutableList<Int>`).
 
-- [Get odd](../src/test/kotlin/com/igorwojda/integer/getodd/readme.md)
-- [Count down](../src/test/kotlin/com/igorwojda/integer/countdown/readme.md)
-- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/readme.md)
-- [Tree traversal](../src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md)
+- [Get odd](../src/test/kotlin/com/igorwojda/integer/getodd/README.md)
+- [Count down](../src/test/kotlin/com/igorwojda/integer/countdown/README.md)
+- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/README.md)
+- [Tree traversal](../src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md)
 
 ## Double pointer 
 
 Problem solved by using double variable pointing to various indexes of the list. We use double pointer instead of nested
 loops which decreases complexity from `O(n^2)` to `O(n)`.
 
-- [Sum zero](../src/test/kotlin/com/igorwojda/list/sumzero/readme.md)
-- [Pair average](../src/test/kotlin/com/igorwojda/list/pairaverage/readme.md)
-- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/readme.md)
-- [Get duplicated arguments](../src/test/kotlin/com/igorwojda/string/getduplicatedarguments/readme.md)
-- [Midpoint](../src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/readme.md)
-- [Circular check](../src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/readme.md)
+- [Sum zero](../src/test/kotlin/com/igorwojda/list/sumzero/README.md)
+- [Pair average](../src/test/kotlin/com/igorwojda/list/pairaverage/README.md)
+- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/README.md)
+- [Get duplicated arguments](../src/test/kotlin/com/igorwojda/string/getduplicatedarguments/README.md)
+- [Midpoint](../src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/README.md)
+- [Circular check](../src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/README.md)
 
 ## Frequency counter
 
 Problems solved by counting occurrence of element. We use frequency counter instead of nested loops which decreases
 complexity from `O(n^2)` to `O(n)`.
 
-- [Count unique values](../src/test/kotlin/com/igorwojda/list/countuniquevalues/readme.md)
-- [Is anagram](../src/test/kotlin/com/igorwojda/string/isanagram/readme.md)
-- [Square equals](../src/test/kotlin/com/igorwojda/list/squareequal/readme.md)
-- [Digit frequency](../src/test/kotlin/com/igorwojda/integer/digitfrequency/readme.md)
-- [Max occurring char](../src/test/kotlin/com/igorwojda/string/maxchar/readme.md)
-- [Get duplicated arguments](../src/test/kotlin/com/igorwojda/string/getduplicatedarguments/readme.md)
-- [Subtract](../src/test/kotlin/com/igorwojda/list/subtract/readme.md)
-- [Has repeated char](../src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/readme.md)
+- [Count unique values](../src/test/kotlin/com/igorwojda/list/countuniquevalues/README.md)
+- [Is anagram](../src/test/kotlin/com/igorwojda/string/isanagram/README.md)
+- [Square equals](../src/test/kotlin/com/igorwojda/list/squareequal/README.md)
+- [Digit frequency](../src/test/kotlin/com/igorwojda/integer/digitfrequency/README.md)
+- [Max occurring char](../src/test/kotlin/com/igorwojda/string/maxchar/README.md)
+- [Get duplicated arguments](../src/test/kotlin/com/igorwojda/string/getduplicatedarguments/README.md)
+- [Subtract](../src/test/kotlin/com/igorwojda/list/subtract/README.md)
+- [Has repeated char](../src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/README.md)
 
 ## Sliding window 
 
 We use sliding window instead of nested loops which decreases complexity from `O(n^2)` to `O(n)`.
 
-- [Max sub list sum](../src/test/kotlin/com/igorwojda/list/maxsublistsum/readme.md)
-- [Min sub list length](../src/test/kotlin/com/igorwojda/list/minsublistlength/readme.md)
+- [Max sub list sum](../src/test/kotlin/com/igorwojda/list/maxsublistsum/README.md)
+- [Min sub list length](../src/test/kotlin/com/igorwojda/list/minsublistlength/README.md)
 
 ## List
 
 ### Search algorithms
 
-- [Linear search](../src/test/kotlin/com/igorwojda/list/search/linearsearch/readme.md)
-- [Binary search](../src/test/kotlin/com/igorwojda/list/search/binarysearch/readme.md)
+- [Linear search](../src/test/kotlin/com/igorwojda/list/search/linearsearch/README.md)
+- [Binary search](../src/test/kotlin/com/igorwojda/list/search/binarysearch/README.md)
 
 ### Sort algorithms
 
-- [Bubble sort](../src/test/kotlin/com/igorwojda/list/sort/bubblesort/readme.md)
-- [Merge sort](../src/test/kotlin/com/igorwojda/list/sort/mergesort/readme.md)
-- [Selection sort](../src/test/kotlin/com/igorwojda/list/sort/selectionsort/readme.md)
-- [Insertion sort](../src/test/kotlin/com/igorwojda/list/sort/insertionsort/readme.md)
-- [Quick sort](../src/test/kotlin/com/igorwojda/list/sort/quicksort/readme.md)
-- [Radix sort](../src/test/kotlin/com/igorwojda/list/sort/radixsort/readme.md)
+- [Bubble sort](../src/test/kotlin/com/igorwojda/list/sort/bubblesort/README.md)
+- [Merge sort](../src/test/kotlin/com/igorwojda/list/sort/mergesort/README.md)
+- [Selection sort](../src/test/kotlin/com/igorwojda/list/sort/selectionsort/README.md)
+- [Insertion sort](../src/test/kotlin/com/igorwojda/list/sort/insertionsort/README.md)
+- [Quick sort](../src/test/kotlin/com/igorwojda/list/sort/quicksort/README.md)
+- [Radix sort](../src/test/kotlin/com/igorwojda/list/sort/radixsort/README.md)
 
 ### Other list challenges
 
-- [Capitalize First](../src/test/kotlin/com/igorwojda/list/capitalizeFirst/readme.md)
-- [Flatten](../src/test/kotlin/com/igorwojda/list/flatten/readme.md)
-- [List chunking](../src/test/kotlin/com/igorwojda/list/listchunk/readme.md)
-- [Max sub-list sum](../src/test/kotlin/com/igorwojda/list/maxsublistsum/readme.md)
-- [Min sub-list length](../src/test/kotlin/com/igorwojda/list/minsublistlength/readme.md)
-- [Find the pair with average](../src/test/kotlin/com/igorwojda/list/pairaverage/readme.md)
-- [Product](../src/test/kotlin/com/igorwojda/list/product/readme.md)
-- [Square compare](../src/test/kotlin/com/igorwojda/list/squareequal/readme.md)
-- [List subtract](../src/test/kotlin/com/igorwojda/list/subtract/readme.md)
-- [Sum zero](../src/test/kotlin/com/igorwojda/list/sumzero/readme.md)
-- [Coins](src/test/kotlin/com/igorwojda/list/coins/readme.md)
+- [Capitalize First](../src/test/kotlin/com/igorwojda/list/capitalizeFirst/README.md)
+- [Flatten](../src/test/kotlin/com/igorwojda/list/flatten/README.md)
+- [List chunking](../src/test/kotlin/com/igorwojda/list/listchunk/README.md)
+- [Max sub-list sum](../src/test/kotlin/com/igorwojda/list/maxsublistsum/README.md)
+- [Min sub-list length](../src/test/kotlin/com/igorwojda/list/minsublistlength/README.md)
+- [Find the pair with average](../src/test/kotlin/com/igorwojda/list/pairaverage/README.md)
+- [Product](../src/test/kotlin/com/igorwojda/list/product/README.md)
+- [Square compare](../src/test/kotlin/com/igorwojda/list/squareequal/README.md)
+- [List subtract](../src/test/kotlin/com/igorwojda/list/subtract/README.md)
+- [Sum zero](../src/test/kotlin/com/igorwojda/list/sumzero/README.md)
+- [Coins](src/test/kotlin/com/igorwojda/list/coins/README.md)
 
 ## Singly Linked List
 
-- [Singly linked list](../src/test/kotlin/com/igorwojda/linkedlist/singly/base/readme.md)
-- [Circular linked list?](../src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/readme.md)
-- [Take n-th element from last](../src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/readme.md)
-- [Midpoint](../src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/readme.md)
+- [Singly linked list](../src/test/kotlin/com/igorwojda/linkedlist/singly/base/README.md)
+- [Circular linked list?](../src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/README.md)
+- [Take n-th element from last](../src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/README.md)
+- [Midpoint](../src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/README.md)
 
 ## Doubly Linked List
 
-- [Doubly linked list](../src/test/kotlin/com/igorwojda/linkedlist/doubly/base/readme.md)
+- [Doubly linked list](../src/test/kotlin/com/igorwojda/linkedlist/doubly/base/README.md)
 
 ## Binary tree
 
-- [Binary Search Tree (insert)](../src/test/kotlin/com/igorwojda/tree/binarytree/insert/readme.md)
-- [Binary Tree (validate)](../src/test/kotlin/com/igorwojda/tree/binarytree/validate/readme.md)
+- [Binary Search Tree (insert)](../src/test/kotlin/com/igorwojda/tree/binarytree/insert/README.md)
+- [Binary Tree (validate)](../src/test/kotlin/com/igorwojda/tree/binarytree/validate/README.md)
 
 ## Integer
 
-- [Add up to](../src/test/kotlin/com/igorwojda/integer/addupto/readme.md)
-- [Count down](../src/test/kotlin/com/igorwojda/integer/countdown/readme.md)
-- [Count up and down](../src/test/kotlin/com/igorwojda/integer/countupanddown/readme.md)
-- [Digit frequency](../src/test/kotlin/com/igorwojda/integer/digitfrequency/readme.md)
-- [Factorial](../src/test/kotlin/com/igorwojda/integer/factorial/readme.md)
-- [Fibonacci](../src/test/kotlin/com/igorwojda/integer/fibonacci/basic/readme.md)
-- [FizzBuzz](../src/test/kotlin/com/igorwojda/integer/fizzbuzz/readme.md)
-- [Recursive cache fibonacci](../src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/readme.md)
-- [Generate all pairs](../src/test/kotlin/com/igorwojda/integer/generateallpairs/readme.md)
-- [Get odd numbers](../src/test/kotlin/com/igorwojda/integer/getodd/readme.md)
-- [Power](../src/test/kotlin/com/igorwojda/integer/power/readme.md)
-- [Print numbers](../src/test/kotlin/com/igorwojda/integer/printnumber/basic/readme.md)
-- [Print numbers with steps](../src/test/kotlin/com/igorwojda/integer/printnumber/steps/readme.md)
-- [Pyramid generator](../src/test/kotlin/com/igorwojda/integer/pyramidgenerator/readme.md)
-- [Reverse Int](../src/test/kotlin/com/igorwojda/integer/reverse/readme.md)
-- [Steps generator](../src/test/kotlin/com/igorwojda/integer/stepsgenerator/readme.md)
+- [Add up to](../src/test/kotlin/com/igorwojda/integer/addupto/README.md)
+- [Count down](../src/test/kotlin/com/igorwojda/integer/countdown/README.md)
+- [Count up and down](../src/test/kotlin/com/igorwojda/integer/countupanddown/README.md)
+- [Digit frequency](../src/test/kotlin/com/igorwojda/integer/digitfrequency/README.md)
+- [Factorial](../src/test/kotlin/com/igorwojda/integer/factorial/README.md)
+- [Fibonacci](../src/test/kotlin/com/igorwojda/integer/fibonacci/basic/README.md)
+- [FizzBuzz](../src/test/kotlin/com/igorwojda/integer/fizzbuzz/README.md)
+- [Recursive cache fibonacci](../src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/README.md)
+- [Generate all pairs](../src/test/kotlin/com/igorwojda/integer/generateallpairs/README.md)
+- [Get odd numbers](../src/test/kotlin/com/igorwojda/integer/getodd/README.md)
+- [Power](../src/test/kotlin/com/igorwojda/integer/power/README.md)
+- [Print numbers](../src/test/kotlin/com/igorwojda/integer/printnumber/basic/README.md)
+- [Print numbers with steps](../src/test/kotlin/com/igorwojda/integer/printnumber/steps/README.md)
+- [Pyramid generator](../src/test/kotlin/com/igorwojda/integer/pyramidgenerator/README.md)
+- [Reverse Int](../src/test/kotlin/com/igorwojda/integer/reverse/README.md)
+- [Steps generator](../src/test/kotlin/com/igorwojda/integer/stepsgenerator/README.md)
 
 ## String
 
-- [Caesar Cipher](../src/test/kotlin/com/igorwojda/string/caesarcipher/readme.md)
-- [Capitalize sentence](../src/test/kotlin/com/igorwojda/string/capitalizesentence/readme.md)
-- [Decapitalize const](../src/test/kotlin/com/igorwojda/string/decapitalizeconst/readme.md)
-- [Get duplicated arguments](../src/test/kotlin/com/igorwojda/string/getduplicatedarguments/readme.md)
-- [Has repeated char](../src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/readme.md)
-- [Is anagram](../src/test/kotlin/com/igorwojda/string/isanagram/readme.md)
-- [Is palindrome](../src/test/kotlin/com/igorwojda/string/ispalindrome/basic/readme.md)
-- [Is tolerant palindrome](../src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/readme.md)
-- [Is permutation palindrome](../src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/readme.md)
-- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/readme.md)
-- [Longest word](../src/test/kotlin/com/igorwojda/string/longestword/readme.md)
-- [Max occurrent char](../src/test/kotlin/com/igorwojda/string/maxchar/readme.md)
-- [Reverse string](../src/test/kotlin/com/igorwojda/string/reverse/readme.md)
-- [Surrounded letter](../src/test/kotlin/com/igorwojda/string/surroundedletter/readme.md)
-- [Find the vowels](../src/test/kotlin/com/igorwojda/string/vowels/readme.md)
-- [Format train route](../src/test/kotlin/com/igorwojda/list/formattrainroute/readme.md)
+- [Caesar Cipher](../src/test/kotlin/com/igorwojda/string/caesarcipher/README.md)
+- [Capitalize sentence](../src/test/kotlin/com/igorwojda/string/capitalizesentence/README.md)
+- [Decapitalize const](../src/test/kotlin/com/igorwojda/string/decapitalizeconst/README.md)
+- [Get duplicated arguments](../src/test/kotlin/com/igorwojda/string/getduplicatedarguments/README.md)
+- [Has repeated char](../src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/README.md)
+- [Is anagram](../src/test/kotlin/com/igorwojda/string/isanagram/README.md)
+- [Is palindrome](../src/test/kotlin/com/igorwojda/string/ispalindrome/basic/README.md)
+- [Is tolerant palindrome](../src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/README.md)
+- [Is permutation palindrome](../src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/README.md)
+- [Is substring](../src/test/kotlin/com/igorwojda/string/issubstring/README.md)
+- [Longest word](../src/test/kotlin/com/igorwojda/string/longestword/README.md)
+- [Max occurrent char](../src/test/kotlin/com/igorwojda/string/maxchar/README.md)
+- [Reverse string](../src/test/kotlin/com/igorwojda/string/reverse/README.md)
+- [Surrounded letter](../src/test/kotlin/com/igorwojda/string/surroundedletter/README.md)
+- [Find the vowels](../src/test/kotlin/com/igorwojda/string/vowels/README.md)
+- [Format train route](../src/test/kotlin/com/igorwojda/list/formattrainroute/README.md)
 
 ## Matrix
 
-- [Spiral matrix generator](../src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/readme.md)
-- [Find rectangle](../src/test/kotlin/com/igorwojda/matrix/findrectangle/readme.md)
+- [Spiral matrix generator](../src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/README.md)
+- [Find rectangle](../src/test/kotlin/com/igorwojda/matrix/findrectangle/README.md)
 
 ## Range
 
-- [Contains range?](../src/test/kotlin/com/igorwojda/range/containsrange/readme.md)
+- [Contains range?](../src/test/kotlin/com/igorwojda/range/containsrange/README.md)
 
 ## Queue
 
-- [Queue](../src/test/kotlin/com/igorwojda/queue/basic/readme.md)
-- [Combine two queues](../src/test/kotlin/com/igorwojda/queue/combine/readme.md)
-- [Tree traversal](../src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md)
+- [Queue](../src/test/kotlin/com/igorwojda/queue/basic/README.md)
+- [Combine two queues](../src/test/kotlin/com/igorwojda/queue/combine/README.md)
+- [Tree traversal](../src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md)
 
 ## Stack
 
-- [Stack](../src/test/kotlin/com/igorwojda/stack/basic/readme.md)
-- [Tree traversal](../src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md)
+- [Stack](../src/test/kotlin/com/igorwojda/stack/basic/README.md)
+- [Tree traversal](../src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md)
 
 ## Heap
 
-- [Max binary heap](../src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/readme.md)
+- [Max binary heap](../src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/README.md)
 
 ## Tree
 
-- [Binary search tree](../src/test/kotlin/com/igorwojda/tree/binarysearchtree/readme.md)
-- [Tree level width](../src/test/kotlin/com/igorwojda/tree/classic/levelwidth/readme.md)
-- [Tree](../src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md)
+- [Binary search tree](../src/test/kotlin/com/igorwojda/tree/binarysearchtree/README.md)
+- [Tree level width](../src/test/kotlin/com/igorwojda/tree/classic/levelwidth/README.md)
+- [Tree](../src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md)
diff --git a/misc/template/challenge/challenge.kt b/misc/template/challenge/Challenge.kt
similarity index 100%
rename from misc/template/challenge/challenge.kt
rename to misc/template/challenge/Challenge.kt
diff --git a/misc/template/challenge/readme.md b/misc/template/challenge/README.md
similarity index 83%
rename from misc/template/challenge/readme.md
rename to misc/template/challenge/README.md
index 41681c78..dc6c9ff2 100644
--- a/misc/template/challenge/readme.md
+++ b/misc/template/challenge/README.md
@@ -6,7 +6,7 @@
 
 ???
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations
 
diff --git a/misc/template/challenge/solution.kt b/misc/template/challenge/Solution.kt
similarity index 100%
rename from misc/template/challenge/solution.kt
rename to misc/template/challenge/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/addupto/challenge.kt b/src/test/kotlin/com/igorwojda/integer/addupto/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/addupto/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/addupto/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/addupto/readme.md b/src/test/kotlin/com/igorwojda/integer/addupto/README.md
similarity index 81%
rename from src/test/kotlin/com/igorwojda/integer/addupto/readme.md
rename to src/test/kotlin/com/igorwojda/integer/addupto/README.md
index 7847afcc..359573a6 100644
--- a/src/test/kotlin/com/igorwojda/integer/addupto/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/addupto/README.md
@@ -4,7 +4,7 @@
 Given positive integer `n` implement a function which calculates sum of all numbers from `1` up to (and including)
 number `n`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/addupto/solution.kt b/src/test/kotlin/com/igorwojda/integer/addupto/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/addupto/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/addupto/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/countdown/challenge.kt b/src/test/kotlin/com/igorwojda/integer/countdown/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/countdown/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/countdown/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/countdown/readme.md b/src/test/kotlin/com/igorwojda/integer/countdown/README.md
similarity index 81%
rename from src/test/kotlin/com/igorwojda/integer/countdown/readme.md
rename to src/test/kotlin/com/igorwojda/integer/countdown/README.md
index 9e5be648..e2146493 100644
--- a/src/test/kotlin/com/igorwojda/integer/countdown/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/countdown/README.md
@@ -4,7 +4,7 @@
 
 Given positive integer `n` implement a function which returns a list containing all steps from `n` to `0`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/countdown/solution.kt b/src/test/kotlin/com/igorwojda/integer/countdown/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/countdown/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/countdown/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/countupanddown/challenge.kt b/src/test/kotlin/com/igorwojda/integer/countupanddown/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/countupanddown/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/countupanddown/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/countupanddown/readme.md b/src/test/kotlin/com/igorwojda/integer/countupanddown/README.md
similarity index 76%
rename from src/test/kotlin/com/igorwojda/integer/countupanddown/readme.md
rename to src/test/kotlin/com/igorwojda/integer/countupanddown/README.md
index 19a75baf..5014843f 100644
--- a/src/test/kotlin/com/igorwojda/integer/countupanddown/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/countupanddown/README.md
@@ -2,14 +2,14 @@
 
 ## Nice to solve before
 
-[Count down](../countdown/readme.md)
+[Count down](../countdown/README.md)
 
 ## Instructions
 
 Given positive integer `n` implement a function which returns a list containing all steps up from `0` to `n` and down to
 `0`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/countupanddown/solution.kt b/src/test/kotlin/com/igorwojda/integer/countupanddown/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/countupanddown/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/countupanddown/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/digitfrequency/challenge.kt b/src/test/kotlin/com/igorwojda/integer/digitfrequency/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/digitfrequency/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/digitfrequency/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/digitfrequency/readme.md b/src/test/kotlin/com/igorwojda/integer/digitfrequency/README.md
similarity index 86%
rename from src/test/kotlin/com/igorwojda/integer/digitfrequency/readme.md
rename to src/test/kotlin/com/igorwojda/integer/digitfrequency/README.md
index ec2b9f9b..e77f80ce 100644
--- a/src/test/kotlin/com/igorwojda/integer/digitfrequency/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/digitfrequency/README.md
@@ -4,7 +4,7 @@
 
 Given two integers implement a function which determines if they have the same frequency of digits.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/digitfrequency/solution.kt b/src/test/kotlin/com/igorwojda/integer/digitfrequency/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/digitfrequency/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/digitfrequency/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/factorial/challenge.kt b/src/test/kotlin/com/igorwojda/integer/factorial/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/factorial/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/factorial/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/factorial/readme.md b/src/test/kotlin/com/igorwojda/integer/factorial/README.md
similarity index 88%
rename from src/test/kotlin/com/igorwojda/integer/factorial/readme.md
rename to src/test/kotlin/com/igorwojda/integer/factorial/README.md
index d6fccab8..8cbbbb76 100644
--- a/src/test/kotlin/com/igorwojda/integer/factorial/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/factorial/README.md
@@ -6,7 +6,7 @@ Given positive integer `n` implement a function, which returns a [factorial](htt
 that integer. Factorial (of positive integer) is number that is created by multiplying all numbers from 1 to `n` eg.
 factorial of `3` (`3!`) is equal to `6` (`3 * 2 * 1`)
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/factorial/solution.kt b/src/test/kotlin/com/igorwojda/integer/factorial/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/factorial/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/factorial/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/fibonacci/basic/challenge.kt b/src/test/kotlin/com/igorwojda/integer/fibonacci/basic/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fibonacci/basic/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/fibonacci/basic/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/fibonacci/basic/readme.md b/src/test/kotlin/com/igorwojda/integer/fibonacci/basic/README.md
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fibonacci/basic/readme.md
rename to src/test/kotlin/com/igorwojda/integer/fibonacci/basic/README.md
diff --git a/src/test/kotlin/com/igorwojda/integer/fibonacci/basic/solution.kt b/src/test/kotlin/com/igorwojda/integer/fibonacci/basic/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fibonacci/basic/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/fibonacci/basic/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/challenge.kt b/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/readme.md b/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/README.md
similarity index 94%
rename from src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/readme.md
rename to src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/README.md
index d7e6cc60..41c12ca9 100644
--- a/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/README.md
@@ -24,6 +24,6 @@ private data class MethodCache(val n: Int, val result: Int)
 If the function is called again with the same arguments, return the precomputed result rather than running the function
 again.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 
diff --git a/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/solution.kt b/src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/fibonacci/recursivecached/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/fizzbuzz/challenge.kt b/src/test/kotlin/com/igorwojda/integer/fizzbuzz/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fizzbuzz/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/fizzbuzz/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/fizzbuzz/readme.md b/src/test/kotlin/com/igorwojda/integer/fizzbuzz/README.md
similarity index 91%
rename from src/test/kotlin/com/igorwojda/integer/fizzbuzz/readme.md
rename to src/test/kotlin/com/igorwojda/integer/fizzbuzz/README.md
index 651b023c..3fd143f9 100644
--- a/src/test/kotlin/com/igorwojda/integer/fizzbuzz/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/fizzbuzz/README.md
@@ -6,7 +6,7 @@ Given positive integer `n` implement a function which returns a list numbers fro
 three list should contain word `Fizz` instead of the number and for the multiples of five list should contain
 word `Buzz`. For numbers which are multiples of both three and five list should contain `FizzBuzz` word.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/fizzbuzz/solution.kt b/src/test/kotlin/com/igorwojda/integer/fizzbuzz/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/fizzbuzz/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/fizzbuzz/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/generateallpairs/challenge.kt b/src/test/kotlin/com/igorwojda/integer/generateallpairs/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/generateallpairs/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/generateallpairs/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/generateallpairs/readme.md b/src/test/kotlin/com/igorwojda/integer/generateallpairs/README.md
similarity index 91%
rename from src/test/kotlin/com/igorwojda/integer/generateallpairs/readme.md
rename to src/test/kotlin/com/igorwojda/integer/generateallpairs/README.md
index e31bd4ff..02cd627a 100644
--- a/src/test/kotlin/com/igorwojda/integer/generateallpairs/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/generateallpairs/README.md
@@ -5,7 +5,7 @@
 Given positive Int `n` implement a function which returns a list of containing pairs with all combinations of numbers
 from `0` to `n`. Use Kotlin [Pair](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-pair/) class.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/generateallpairs/solution.kt b/src/test/kotlin/com/igorwojda/integer/generateallpairs/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/generateallpairs/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/generateallpairs/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/getodd/challenge.kt b/src/test/kotlin/com/igorwojda/integer/getodd/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/getodd/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/getodd/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/getodd/readme.md b/src/test/kotlin/com/igorwojda/integer/getodd/README.md
similarity index 75%
rename from src/test/kotlin/com/igorwojda/integer/getodd/readme.md
rename to src/test/kotlin/com/igorwojda/integer/getodd/README.md
index bd9f7cdc..a79fd615 100644
--- a/src/test/kotlin/com/igorwojda/integer/getodd/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/getodd/README.md
@@ -2,13 +2,13 @@
 
 ## Nice to solve before
 
-- [Count down](../countdown/readme.md)
+- [Count down](../countdown/README.md)
 
 ## Instructions
 
 Given a list of integers return a list that contains only odd integers (only integers which are not a multiple of `2`).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/getodd/solution.kt b/src/test/kotlin/com/igorwojda/integer/getodd/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/getodd/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/getodd/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/power/challenge.kt b/src/test/kotlin/com/igorwojda/integer/power/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/power/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/power/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/power/readme.md b/src/test/kotlin/com/igorwojda/integer/power/README.md
similarity index 87%
rename from src/test/kotlin/com/igorwojda/integer/power/readme.md
rename to src/test/kotlin/com/igorwojda/integer/power/README.md
index c85988bd..544e7df9 100644
--- a/src/test/kotlin/com/igorwojda/integer/power/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/power/README.md
@@ -5,7 +5,7 @@
 Given positive integer `base` and positive integer `exponent` implement a function which calculates power of base of
 exponent. This function should mimic functionality of [Math.pow](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.math/pow.html).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/power/solution.kt b/src/test/kotlin/com/igorwojda/integer/power/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/power/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/power/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/printnumber/basic/challenge.kt b/src/test/kotlin/com/igorwojda/integer/printnumber/basic/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/printnumber/basic/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/printnumber/basic/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/printnumber/basic/readme.md b/src/test/kotlin/com/igorwojda/integer/printnumber/basic/README.md
similarity index 85%
rename from src/test/kotlin/com/igorwojda/integer/printnumber/basic/readme.md
rename to src/test/kotlin/com/igorwojda/integer/printnumber/basic/README.md
index facbc414..23aad60b 100644
--- a/src/test/kotlin/com/igorwojda/integer/printnumber/basic/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/printnumber/basic/README.md
@@ -5,7 +5,7 @@
 Given positive integer `n` implement a function which returns a list representing all numbers from `n` to `1`. If `n`
 value is zero then empty list should be returned.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/printnumber/basic/solution.kt b/src/test/kotlin/com/igorwojda/integer/printnumber/basic/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/printnumber/basic/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/printnumber/basic/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/printnumber/steps/challenge.kt b/src/test/kotlin/com/igorwojda/integer/printnumber/steps/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/printnumber/steps/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/printnumber/steps/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/printnumber/steps/readme.md b/src/test/kotlin/com/igorwojda/integer/printnumber/steps/README.md
similarity index 88%
rename from src/test/kotlin/com/igorwojda/integer/printnumber/steps/readme.md
rename to src/test/kotlin/com/igorwojda/integer/printnumber/steps/README.md
index fc7ba96d..4f77cbce 100644
--- a/src/test/kotlin/com/igorwojda/integer/printnumber/steps/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/printnumber/steps/README.md
@@ -5,7 +5,7 @@
 Given positive integer `n` and integer `step` implement a function which returns a list representing all numbers from
 `n` to `1` taking `step` into consideration. If `n` value is zero then empty list should be returned.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/printnumber/steps/solution.kt b/src/test/kotlin/com/igorwojda/integer/printnumber/steps/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/printnumber/steps/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/printnumber/steps/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/challenge.kt b/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/pyramidgenerator/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/pyramidgenerator/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/readme.md b/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/README.md
similarity index 89%
rename from src/test/kotlin/com/igorwojda/integer/pyramidgenerator/readme.md
rename to src/test/kotlin/com/igorwojda/integer/pyramidgenerator/README.md
index 8f551b82..6f5e100c 100644
--- a/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/README.md
@@ -6,7 +6,7 @@ Given a positive integer `n` implement a function which returns a list represent
 levels. The function should console log a generatePyramid shape with N levels using the `#` character. Make sure the
 generatePyramid has spaces on both the left and right hand sides.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/solution.kt b/src/test/kotlin/com/igorwojda/integer/pyramidgenerator/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/pyramidgenerator/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/pyramidgenerator/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/reverse/challenge.kt b/src/test/kotlin/com/igorwojda/integer/reverse/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/reverse/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/reverse/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/reverse/readme.md b/src/test/kotlin/com/igorwojda/integer/reverse/README.md
similarity index 83%
rename from src/test/kotlin/com/igorwojda/integer/reverse/readme.md
rename to src/test/kotlin/com/igorwojda/integer/reverse/README.md
index 76fc047b..321d532a 100644
--- a/src/test/kotlin/com/igorwojda/integer/reverse/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/reverse/README.md
@@ -4,7 +4,7 @@
 
 Given an integer `n`, return an integer that is the reverse ordering of digits.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/reverse/solution.kt b/src/test/kotlin/com/igorwojda/integer/reverse/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/reverse/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/reverse/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/stepsgenerator/challenge.kt b/src/test/kotlin/com/igorwojda/integer/stepsgenerator/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/stepsgenerator/challenge.kt
rename to src/test/kotlin/com/igorwojda/integer/stepsgenerator/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/integer/stepsgenerator/readme.md b/src/test/kotlin/com/igorwojda/integer/stepsgenerator/README.md
similarity index 88%
rename from src/test/kotlin/com/igorwojda/integer/stepsgenerator/readme.md
rename to src/test/kotlin/com/igorwojda/integer/stepsgenerator/README.md
index aa338fd4..802f5af9 100644
--- a/src/test/kotlin/com/igorwojda/integer/stepsgenerator/readme.md
+++ b/src/test/kotlin/com/igorwojda/integer/stepsgenerator/README.md
@@ -5,7 +5,7 @@
 Given a positive integer `n` implement a function which returns a list representing the generated steps with `n` levels
 using the `#` character. Make sure the step has appropriate number of spaces on the right hand side!
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/integer/stepsgenerator/solution.kt b/src/test/kotlin/com/igorwojda/integer/stepsgenerator/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/integer/stepsgenerator/solution.kt
rename to src/test/kotlin/com/igorwojda/integer/stepsgenerator/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/challenge.kt b/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/doubly/base/challenge.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/doubly/base/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/readme.md b/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/README.md
similarity index 98%
rename from src/test/kotlin/com/igorwojda/linkedlist/doubly/base/readme.md
rename to src/test/kotlin/com/igorwojda/linkedlist/doubly/base/README.md
index 32814b2c..7b68c336 100644
--- a/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/readme.md
+++ b/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/README.md
@@ -2,7 +2,7 @@
 
 ## Nice to solve before
 
-[Singly linked List](../../singly/base/readme.md)
+[Singly linked List](../../singly/base/README.md)
 
 ### Instructions
 
@@ -14,7 +14,7 @@ mistakes. That's why each step has one or more tests associated with it. Tests a
 staring each step we will have to enable all tests related to given step by uncommenting it. To quickly uncomment the
 test select all lines containing test method and press `Cmd + /` keys (`Comment with line Comment` action).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ### 1. constructor `DoublyLinkedList<E>()`
 
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/solution.kt b/src/test/kotlin/com/igorwojda/linkedlist/doubly/base/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/doubly/base/solution.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/doubly/base/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/base/challenge.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/base/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/base/challenge.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/base/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/base/readme.md b/src/test/kotlin/com/igorwojda/linkedlist/singly/base/README.md
similarity index 99%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/base/readme.md
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/base/README.md
index 0521fb1c..4db2c4ab 100644
--- a/src/test/kotlin/com/igorwojda/linkedlist/singly/base/readme.md
+++ b/src/test/kotlin/com/igorwojda/linkedlist/singly/base/README.md
@@ -10,7 +10,7 @@ mistakes. That's why each step has one or more tests associated with it. Tests a
 staring each step we will have to enable all tests related to given step by uncommenting it. To quickly uncomment the
 test select all lines containing test method and press `Cmd + /` keys (`Comment with line Comment` action).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ### 1. constructor `SinglyLinkedList<E>()`
 
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/base/solution.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/base/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/base/solution.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/base/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/challenge.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/challenge.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/readme.md b/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/README.md
similarity index 91%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/readme.md
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/README.md
index b58f1b54..3620ee33 100644
--- a/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/readme.md
+++ b/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/README.md
@@ -2,13 +2,13 @@
 
 ## Nice to solve before
 
-[Singly linked List](../base/readme.md)
+[Singly linked List](../base/README.md)
 
 ## Instructions
 
 Given a linked list, return true if the list is circular, false if it is not.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/solution.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/solution.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/circularcheck/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/challenge.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/challenge.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/readme.md b/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/README.md
similarity index 78%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/readme.md
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/README.md
index a25af724..c2218d08 100644
--- a/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/readme.md
+++ b/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/README.md
@@ -2,16 +2,16 @@
 
 ## Nice to solve before
 
-- [Singly linked list](../base/readme.md)
-- [Midpoint](../midpoint/readme.md)
-- [Circular check](../circularcheck/readme.md)
+- [Singly linked list](../base/README.md)
+- [Midpoint](../midpoint/README.md)
+- [Circular check](../circularcheck/README.md)
 
 ## Instructions
 
 Given a linked list, return the element n positions from the last node in the list. Assume that `endIndex` will always
 be less than the length of the list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations
 
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/solution.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/solution.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/fromlast/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/challenge.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/challenge.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/readme.md b/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/README.md
similarity index 96%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/readme.md
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/README.md
index c2a603c6..28dc3283 100644
--- a/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/readme.md
+++ b/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/README.md
@@ -13,7 +13,7 @@ We are using version of linked list that implements Kotlin
 [Iterator](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-iterator/index.html) interface, so we can
 use `forEach` instead of `while` loop.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations
 
diff --git a/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/solution.kt b/src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/solution.kt
rename to src/test/kotlin/com/igorwojda/linkedlist/singly/midpoint/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/capitalizeFirst/challenge.kt b/src/test/kotlin/com/igorwojda/list/capitalizeFirst/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/capitalizeFirst/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/capitalizeFirst/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/capitalizeFirst/readme.md b/src/test/kotlin/com/igorwojda/list/capitalizeFirst/README.md
similarity index 84%
rename from src/test/kotlin/com/igorwojda/list/capitalizeFirst/readme.md
rename to src/test/kotlin/com/igorwojda/list/capitalizeFirst/README.md
index 0412741f..a90bebfd 100644
--- a/src/test/kotlin/com/igorwojda/list/capitalizeFirst/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/capitalizeFirst/README.md
@@ -4,7 +4,7 @@
 
 Given list of strings implement a **recursive** function which will capitalize first letter of each string in the list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
@@ -12,4 +12,4 @@ Given list of strings implement a **recursive** function which will capitalize f
 capitalizeFirst(listOf("igor")) // listOf("Igor")
 
 capitalizeFirst(listOf("igor", "wojda")) // listOf("Igor", "Wojda")
-```
\ No newline at end of file
+```
diff --git a/src/test/kotlin/com/igorwojda/list/capitalizeFirst/solution.kt b/src/test/kotlin/com/igorwojda/list/capitalizeFirst/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/capitalizeFirst/solution.kt
rename to src/test/kotlin/com/igorwojda/list/capitalizeFirst/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/coins/challenge.kt b/src/test/kotlin/com/igorwojda/list/coins/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/coins/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/coins/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/coins/readme.md b/src/test/kotlin/com/igorwojda/list/coins/README.md
similarity index 87%
rename from src/test/kotlin/com/igorwojda/list/coins/readme.md
rename to src/test/kotlin/com/igorwojda/list/coins/README.md
index 72da436c..1d77933d 100644
--- a/src/test/kotlin/com/igorwojda/list/coins/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/coins/README.md
@@ -5,7 +5,7 @@
 Given an amount of money and an array of coins write a method that computes the number of ways to make the amount of
 money with coins of the available coins.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/coins/solution.kt b/src/test/kotlin/com/igorwojda/list/coins/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/coins/solution.kt
rename to src/test/kotlin/com/igorwojda/list/coins/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/countuniquevalues/challenge.kt b/src/test/kotlin/com/igorwojda/list/countuniquevalues/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/countuniquevalues/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/countuniquevalues/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/countuniquevalues/readme.md b/src/test/kotlin/com/igorwojda/list/countuniquevalues/README.md
similarity index 83%
rename from src/test/kotlin/com/igorwojda/list/countuniquevalues/readme.md
rename to src/test/kotlin/com/igorwojda/list/countuniquevalues/README.md
index c53eaefb..f8bc6f65 100644
--- a/src/test/kotlin/com/igorwojda/list/countuniquevalues/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/countuniquevalues/README.md
@@ -4,7 +4,7 @@
 
 Given a sorted list of integers implement a function which counts the unique values.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/countuniquevalues/solution.kt b/src/test/kotlin/com/igorwojda/list/countuniquevalues/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/countuniquevalues/solution.kt
rename to src/test/kotlin/com/igorwojda/list/countuniquevalues/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/flatten/challenge.kt b/src/test/kotlin/com/igorwojda/list/flatten/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/flatten/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/flatten/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/flatten/readme.md b/src/test/kotlin/com/igorwojda/list/flatten/README.md
similarity index 91%
rename from src/test/kotlin/com/igorwojda/list/flatten/readme.md
rename to src/test/kotlin/com/igorwojda/list/flatten/README.md
index aaba3d4d..64b9e5b1 100644
--- a/src/test/kotlin/com/igorwojda/list/flatten/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/flatten/README.md
@@ -7,7 +7,7 @@
 Given list containing items (integer, lists, sub-lists) implement **recursive** function which returns list with all
 values flattened. This function mimics behaviour of Kotlin build in ` flatten` method.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations
 
@@ -29,4 +29,4 @@ flatten(listOf(1), listOf(listOf(2), listOf(listOf(3)))) // 1, 2, 3
 <details>
 <summary>Hint 1</summary>
 Use helper recursive function.
-</details>
\ No newline at end of file
+</details>
diff --git a/src/test/kotlin/com/igorwojda/list/flatten/solution.kt b/src/test/kotlin/com/igorwojda/list/flatten/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/flatten/solution.kt
rename to src/test/kotlin/com/igorwojda/list/flatten/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/formattrainroute/challenge.kt b/src/test/kotlin/com/igorwojda/list/formattrainroute/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/formattrainroute/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/formattrainroute/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/formattrainroute/readme.md b/src/test/kotlin/com/igorwojda/list/formattrainroute/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/list/formattrainroute/readme.md
rename to src/test/kotlin/com/igorwojda/list/formattrainroute/README.md
index 0a30a373..6fe5bdc5 100644
--- a/src/test/kotlin/com/igorwojda/list/formattrainroute/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/formattrainroute/README.md
@@ -8,7 +8,7 @@ Given list of strings representing train station names implement a function whic
 - If list contains single train station name, then return `Train is calling at stationName`
 - If list contains multiple train station names, then return comma separated station names, but the last two names are separated by `and` word.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/formattrainroute/solution.kt b/src/test/kotlin/com/igorwojda/list/formattrainroute/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/formattrainroute/solution.kt
rename to src/test/kotlin/com/igorwojda/list/formattrainroute/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/listchunk/challenge.kt b/src/test/kotlin/com/igorwojda/list/listchunk/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/listchunk/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/listchunk/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/listchunk/readme.md b/src/test/kotlin/com/igorwojda/list/listchunk/README.md
similarity index 89%
rename from src/test/kotlin/com/igorwojda/list/listchunk/readme.md
rename to src/test/kotlin/com/igorwojda/list/listchunk/README.md
index 92efed71..6f8b4663 100644
--- a/src/test/kotlin/com/igorwojda/list/listchunk/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/listchunk/README.md
@@ -4,7 +4,7 @@
 
 Given a list and chunk size, divide the list into multiple sub lists where each sub-list is of length of chunk size.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/listchunk/solution.kt b/src/test/kotlin/com/igorwojda/list/listchunk/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/listchunk/solution.kt
rename to src/test/kotlin/com/igorwojda/list/listchunk/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/maxsublistsum/challenge.kt b/src/test/kotlin/com/igorwojda/list/maxsublistsum/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/maxsublistsum/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/maxsublistsum/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/maxsublistsum/readme.md b/src/test/kotlin/com/igorwojda/list/maxsublistsum/README.md
similarity index 89%
rename from src/test/kotlin/com/igorwojda/list/maxsublistsum/readme.md
rename to src/test/kotlin/com/igorwojda/list/maxsublistsum/README.md
index 98bacd10..72998d60 100644
--- a/src/test/kotlin/com/igorwojda/list/maxsublistsum/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/maxsublistsum/README.md
@@ -8,7 +8,7 @@ elements in the `list` (sum of `n` digits next to another that have the largest
 
 You can use helper `max` function to deal with Kotlin nullability.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
@@ -25,4 +25,4 @@ maxSubListSum(listOf(4, 2, 7, 5, 8, 9, 5, 1), 3) // 22
 <details>
 <summary>Hint 1</summary>
 Use sliding window
-</details>
\ No newline at end of file
+</details>
diff --git a/src/test/kotlin/com/igorwojda/list/maxsublistsum/solution.kt b/src/test/kotlin/com/igorwojda/list/maxsublistsum/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/maxsublistsum/solution.kt
rename to src/test/kotlin/com/igorwojda/list/maxsublistsum/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/minsublistlength/challenge.kt b/src/test/kotlin/com/igorwojda/list/minsublistlength/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/minsublistlength/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/minsublistlength/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/minsublistlength/readme.md b/src/test/kotlin/com/igorwojda/list/minsublistlength/README.md
similarity index 92%
rename from src/test/kotlin/com/igorwojda/list/minsublistlength/readme.md
rename to src/test/kotlin/com/igorwojda/list/minsublistlength/README.md
index 24bfe201..bac8e93b 100644
--- a/src/test/kotlin/com/igorwojda/list/minsublistlength/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/minsublistlength/README.md
@@ -7,7 +7,7 @@ where sum all elements is equal or greater than `n`
 
 You can use helper `min` function to deal with Kotlin nullability.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/minsublistlength/solution.kt b/src/test/kotlin/com/igorwojda/list/minsublistlength/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/minsublistlength/solution.kt
rename to src/test/kotlin/com/igorwojda/list/minsublistlength/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/pairaverage/challenge.kt b/src/test/kotlin/com/igorwojda/list/pairaverage/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/pairaverage/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/pairaverage/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/pairaverage/readme.md b/src/test/kotlin/com/igorwojda/list/pairaverage/README.md
similarity index 90%
rename from src/test/kotlin/com/igorwojda/list/pairaverage/readme.md
rename to src/test/kotlin/com/igorwojda/list/pairaverage/README.md
index 9414f174..ae6e8a1d 100644
--- a/src/test/kotlin/com/igorwojda/list/pairaverage/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/pairaverage/README.md
@@ -5,7 +5,7 @@
 Given sorted list of integers and target average implement a function which determine if there is a pair of values in
 the list where their average equals target average.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/pairaverage/solution.kt b/src/test/kotlin/com/igorwojda/list/pairaverage/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/pairaverage/solution.kt
rename to src/test/kotlin/com/igorwojda/list/pairaverage/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/product/challenge.kt b/src/test/kotlin/com/igorwojda/list/product/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/product/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/product/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/product/readme.md b/src/test/kotlin/com/igorwojda/list/product/README.md
similarity index 86%
rename from src/test/kotlin/com/igorwojda/list/product/readme.md
rename to src/test/kotlin/com/igorwojda/list/product/README.md
index 06fe8af0..0a999d0d 100644
--- a/src/test/kotlin/com/igorwojda/list/product/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/product/README.md
@@ -4,7 +4,7 @@
 
 Given a list of integers implement a function which returns the product of all numbers in the list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/product/solution.kt b/src/test/kotlin/com/igorwojda/list/product/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/product/solution.kt
rename to src/test/kotlin/com/igorwojda/list/product/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/search/binarysearch/challenge.kt b/src/test/kotlin/com/igorwojda/list/search/binarysearch/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/search/binarysearch/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/search/binarysearch/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/search/binarysearch/readme.md b/src/test/kotlin/com/igorwojda/list/search/binarysearch/README.md
similarity index 95%
rename from src/test/kotlin/com/igorwojda/list/search/binarysearch/readme.md
rename to src/test/kotlin/com/igorwojda/list/search/binarysearch/README.md
index 6653eb56..b3dbab13 100644
--- a/src/test/kotlin/com/igorwojda/list/search/binarysearch/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/search/binarysearch/README.md
@@ -6,7 +6,7 @@ Given list of **sorted** elements and a element return index of that element in
 found. Use
 [binary search](https://www.youtube.com/watch?v=T2sFYY-fT5o) algorithm.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Algorithm
 We ignore half of the elements after each loop.
diff --git a/src/test/kotlin/com/igorwojda/list/search/binarysearch/solution.kt b/src/test/kotlin/com/igorwojda/list/search/binarysearch/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/search/binarysearch/solution.kt
rename to src/test/kotlin/com/igorwojda/list/search/binarysearch/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/search/linearsearch/challenge.kt b/src/test/kotlin/com/igorwojda/list/search/linearsearch/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/search/linearsearch/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/search/linearsearch/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/search/linearsearch/readme.md b/src/test/kotlin/com/igorwojda/list/search/linearsearch/README.md
similarity index 89%
rename from src/test/kotlin/com/igorwojda/list/search/linearsearch/readme.md
rename to src/test/kotlin/com/igorwojda/list/search/linearsearch/README.md
index f1317f20..c773ddbb 100644
--- a/src/test/kotlin/com/igorwojda/list/search/linearsearch/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/search/linearsearch/README.md
@@ -4,7 +4,7 @@
 
 Given list of strings and a string return index of th value in the list or `-1` if value was not found.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations
 
diff --git a/src/test/kotlin/com/igorwojda/list/search/linearsearch/solution.kt b/src/test/kotlin/com/igorwojda/list/search/linearsearch/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/search/linearsearch/solution.kt
rename to src/test/kotlin/com/igorwojda/list/search/linearsearch/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/bubblesort/challenge.kt b/src/test/kotlin/com/igorwojda/list/sort/bubblesort/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/bubblesort/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sort/bubblesort/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/bubblesort/readme.md b/src/test/kotlin/com/igorwojda/list/sort/bubblesort/README.md
similarity index 96%
rename from src/test/kotlin/com/igorwojda/list/sort/bubblesort/readme.md
rename to src/test/kotlin/com/igorwojda/list/sort/bubblesort/README.md
index fc00408d..4e344c9f 100644
--- a/src/test/kotlin/com/igorwojda/list/sort/bubblesort/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sort/bubblesort/README.md
@@ -11,7 +11,7 @@ Starting from the beginning of the list, compare every adjacent pair, swap their
 order (the latter one is smaller than the former one). After each iteration, one less element (the last one)
 is needed to be compared until there are no more elements left to be compared.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/sort/bubblesort/solution.kt b/src/test/kotlin/com/igorwojda/list/sort/bubblesort/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/bubblesort/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sort/bubblesort/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/insertionsort/challenge.kt b/src/test/kotlin/com/igorwojda/list/sort/insertionsort/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/insertionsort/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sort/insertionsort/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/insertionsort/readme.md b/src/test/kotlin/com/igorwojda/list/sort/insertionsort/README.md
similarity index 89%
rename from src/test/kotlin/com/igorwojda/list/sort/insertionsort/readme.md
rename to src/test/kotlin/com/igorwojda/list/sort/insertionsort/README.md
index 5f717cd2..d06cba71 100644
--- a/src/test/kotlin/com/igorwojda/list/sort/insertionsort/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sort/insertionsort/README.md
@@ -12,5 +12,5 @@ Sort list of numbers from lowest number to greatest number using
 - Continue to next element and if it is in the incorrect order, iterate through "sorted portion" to place element at
   correct position.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
diff --git a/src/test/kotlin/com/igorwojda/list/sort/insertionsort/solution.kt b/src/test/kotlin/com/igorwojda/list/sort/insertionsort/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/insertionsort/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sort/insertionsort/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/mergesort/challenge.kt b/src/test/kotlin/com/igorwojda/list/sort/mergesort/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/mergesort/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sort/mergesort/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/mergesort/readme.md b/src/test/kotlin/com/igorwojda/list/sort/mergesort/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/list/sort/mergesort/readme.md
rename to src/test/kotlin/com/igorwojda/list/sort/mergesort/README.md
index 493eb886..34eff70a 100644
--- a/src/test/kotlin/com/igorwojda/list/sort/mergesort/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sort/mergesort/README.md
@@ -11,7 +11,7 @@ Algorithm:
 4. Merge sub-lists to produce new sorted sub-lists until there is only one sub-list remaining. This will be the sorted
    list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/sort/mergesort/solution.kt b/src/test/kotlin/com/igorwojda/list/sort/mergesort/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/mergesort/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sort/mergesort/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/quicksort/challenge.kt b/src/test/kotlin/com/igorwojda/list/sort/quicksort/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/quicksort/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sort/quicksort/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/quicksort/readme.md b/src/test/kotlin/com/igorwojda/list/sort/quicksort/README.md
similarity index 92%
rename from src/test/kotlin/com/igorwojda/list/sort/quicksort/readme.md
rename to src/test/kotlin/com/igorwojda/list/sort/quicksort/README.md
index d2cf99df..a43d9d5a 100644
--- a/src/test/kotlin/com/igorwojda/list/sort/quicksort/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sort/quicksort/README.md
@@ -13,4 +13,4 @@ Algorithm:
 - Recursively repeat the process for left partition (element on the left side of pivot) and right partition (element on
   the right side of the pivot)
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
diff --git a/src/test/kotlin/com/igorwojda/list/sort/quicksort/solution.kt b/src/test/kotlin/com/igorwojda/list/sort/quicksort/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/quicksort/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sort/quicksort/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/radixsort/challenge.kt b/src/test/kotlin/com/igorwojda/list/sort/radixsort/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/radixsort/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sort/radixsort/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/radixsort/readme.md b/src/test/kotlin/com/igorwojda/list/sort/radixsort/README.md
similarity index 97%
rename from src/test/kotlin/com/igorwojda/list/sort/radixsort/readme.md
rename to src/test/kotlin/com/igorwojda/list/sort/radixsort/README.md
index 5368198b..068db53f 100644
--- a/src/test/kotlin/com/igorwojda/list/sort/radixsort/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sort/radixsort/README.md
@@ -5,7 +5,7 @@
 Sort list of numbers from lowest number to greatest number using [radix sort](https://en.wikipedia.org/wiki/Radix_sort).
 Algorithm needs to support only positive integers.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Steps
 
diff --git a/src/test/kotlin/com/igorwojda/list/sort/radixsort/solution.kt b/src/test/kotlin/com/igorwojda/list/sort/radixsort/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/radixsort/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sort/radixsort/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/selectionsort/challenge.kt b/src/test/kotlin/com/igorwojda/list/sort/selectionsort/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/selectionsort/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sort/selectionsort/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sort/selectionsort/readme.md b/src/test/kotlin/com/igorwojda/list/sort/selectionsort/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/list/sort/selectionsort/readme.md
rename to src/test/kotlin/com/igorwojda/list/sort/selectionsort/README.md
index 5410633b..b00a5952 100644
--- a/src/test/kotlin/com/igorwojda/list/sort/selectionsort/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sort/selectionsort/README.md
@@ -8,7 +8,7 @@ Sort list of numbers from lowest number to greatest number using
 Algorithm: Sort an list by repeatedly finding the minimum element (ascending order) from unsorted part and putting it at
 the beginning of the list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/sort/selectionsort/solution.kt b/src/test/kotlin/com/igorwojda/list/sort/selectionsort/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sort/selectionsort/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sort/selectionsort/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/squareequal/challenge.kt b/src/test/kotlin/com/igorwojda/list/squareequal/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/squareequal/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/squareequal/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/squareequal/readme.md b/src/test/kotlin/com/igorwojda/list/squareequal/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/list/squareequal/readme.md
rename to src/test/kotlin/com/igorwojda/list/squareequal/README.md
index 0cd6b5d6..1a404fc8 100644
--- a/src/test/kotlin/com/igorwojda/list/squareequal/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/squareequal/README.md
@@ -6,7 +6,7 @@ Given two lists of integers implement a function which returns `true` if every v
 corresponding value squared in the second list. The frequency of values must be the same eg. if there are two values in
 first list, two exactly two squared values must exist in second list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/squareequal/solution.kt b/src/test/kotlin/com/igorwojda/list/squareequal/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/squareequal/solution.kt
rename to src/test/kotlin/com/igorwojda/list/squareequal/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/subtract/challenge.kt b/src/test/kotlin/com/igorwojda/list/subtract/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/subtract/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/subtract/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/subtract/readme.md b/src/test/kotlin/com/igorwojda/list/subtract/README.md
similarity index 77%
rename from src/test/kotlin/com/igorwojda/list/subtract/readme.md
rename to src/test/kotlin/com/igorwojda/list/subtract/README.md
index d30577aa..b19a1bad 100644
--- a/src/test/kotlin/com/igorwojda/list/subtract/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/subtract/README.md
@@ -2,11 +2,11 @@
 
 ## Nice to solve before
 
-- [Is anagram](../../string/isanagram/readme.md)
-- [Square equals](../squareequal/readme.md)
-- [Digit frequency](../../integer/digitfrequency/readme.md)
-- [Max occurring char](../../string/maxchar/readme.md)
-- [Get duplicated arguments](../../string/getduplicatedarguments/readme.md)
+- [Is anagram](../../string/isanagram/README.md)
+- [Square equals](../squareequal/README.md)
+- [Digit frequency](../../integer/digitfrequency/README.md)
+- [Max occurring char](../../string/maxchar/README.md)
+- [Get duplicated arguments](../../string/getduplicatedarguments/README.md)
 
 ## Instructions
 
@@ -15,7 +15,7 @@ to obtain second list (what elements needs to be removed from first list so it i
 may be more than one element with the same value. For simplicity we assume that input is always correct (it is always
 possible to remove values from first list to form second list).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/subtract/solution.kt b/src/test/kotlin/com/igorwojda/list/subtract/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/subtract/solution.kt
rename to src/test/kotlin/com/igorwojda/list/subtract/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sumzero/challenge.kt b/src/test/kotlin/com/igorwojda/list/sumzero/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sumzero/challenge.kt
rename to src/test/kotlin/com/igorwojda/list/sumzero/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/list/sumzero/readme.md b/src/test/kotlin/com/igorwojda/list/sumzero/README.md
similarity index 88%
rename from src/test/kotlin/com/igorwojda/list/sumzero/readme.md
rename to src/test/kotlin/com/igorwojda/list/sumzero/README.md
index be4da3ac..fef411c1 100644
--- a/src/test/kotlin/com/igorwojda/list/sumzero/readme.md
+++ b/src/test/kotlin/com/igorwojda/list/sumzero/README.md
@@ -5,7 +5,7 @@
 Given sorted list of integers implement a function which finds the first pair where the sum equals to `0`. Return an
 pair that includes both values that sum to zero or null if a pair does not exist.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/list/sumzero/solution.kt b/src/test/kotlin/com/igorwojda/list/sumzero/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/list/sumzero/solution.kt
rename to src/test/kotlin/com/igorwojda/list/sumzero/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/matrix/findallrectangles/challenge.kt b/src/test/kotlin/com/igorwojda/matrix/findallrectangles/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/matrix/findallrectangles/challenge.kt
rename to src/test/kotlin/com/igorwojda/matrix/findallrectangles/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/matrix/findallrectangles/readme.md b/src/test/kotlin/com/igorwojda/matrix/findallrectangles/README.md
similarity index 91%
rename from src/test/kotlin/com/igorwojda/matrix/findallrectangles/readme.md
rename to src/test/kotlin/com/igorwojda/matrix/findallrectangles/README.md
index d3b6d657..577a8465 100644
--- a/src/test/kotlin/com/igorwojda/matrix/findallrectangles/readme.md
+++ b/src/test/kotlin/com/igorwojda/matrix/findallrectangles/README.md
@@ -8,7 +8,7 @@ rectangles of 0s on a background of 1s.
 Write a function that takes in the image and returns list containing coordinates of top-left and bottom-right pixels
 represented of each rectangle:
 
-[challenge.kt](challenge.kt) | [solution](solution.kt)
+[Challenge.kt](Challenge.kt) | [solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/matrix/findallrectangles/solution.kt b/src/test/kotlin/com/igorwojda/matrix/findallrectangles/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/matrix/findallrectangles/solution.kt
rename to src/test/kotlin/com/igorwojda/matrix/findallrectangles/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/matrix/findrectangle/challenge.kt b/src/test/kotlin/com/igorwojda/matrix/findrectangle/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/matrix/findrectangle/challenge.kt
rename to src/test/kotlin/com/igorwojda/matrix/findrectangle/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/matrix/findrectangle/readme.md b/src/test/kotlin/com/igorwojda/matrix/findrectangle/README.md
similarity index 94%
rename from src/test/kotlin/com/igorwojda/matrix/findrectangle/readme.md
rename to src/test/kotlin/com/igorwojda/matrix/findrectangle/README.md
index 584bda70..dcce3697 100644
--- a/src/test/kotlin/com/igorwojda/matrix/findrectangle/readme.md
+++ b/src/test/kotlin/com/igorwojda/matrix/findrectangle/README.md
@@ -8,7 +8,7 @@ rectangle of 0s on a background of 1s.
 Write a function that takes in the image and returns list containing coordinates of top-left and bottom-right pixels
 represented as list of internees:
 
-[challenge.kt](challenge.kt) | [solution](solution.kt)
+[Challenge.kt](Challenge.kt) | [solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/matrix/findrectangle/solution.kt b/src/test/kotlin/com/igorwojda/matrix/findrectangle/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/matrix/findrectangle/solution.kt
rename to src/test/kotlin/com/igorwojda/matrix/findrectangle/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/challenge.kt b/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/challenge.kt
rename to src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/readme.md b/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/README.md
similarity index 91%
rename from src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/readme.md
rename to src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/README.md
index ef38d4db..f946b3fb 100644
--- a/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/readme.md
+++ b/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/README.md
@@ -5,7 +5,7 @@
 Given integer `n` implement a function which generates a spiral numbers matrix (size `n` x `n`). Numbers in matrix are
 placed according to spiral - starting top left corner and then go right, down, left, up, right...
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/solution.kt b/src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/solution.kt
rename to src/test/kotlin/com/igorwojda/matrix/spiralmatrixgenerator/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/queue/basic/challenge.kt b/src/test/kotlin/com/igorwojda/queue/basic/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/queue/basic/challenge.kt
rename to src/test/kotlin/com/igorwojda/queue/basic/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/queue/basic/readme.md b/src/test/kotlin/com/igorwojda/queue/basic/README.md
similarity index 92%
rename from src/test/kotlin/com/igorwojda/queue/basic/readme.md
rename to src/test/kotlin/com/igorwojda/queue/basic/README.md
index be1db5a6..7891ad9f 100644
--- a/src/test/kotlin/com/igorwojda/queue/basic/readme.md
+++ b/src/test/kotlin/com/igorwojda/queue/basic/README.md
@@ -2,7 +2,7 @@
 
 ## Nice to solve before
 
-[Stack](../../stack/basic/readme.md)
+[Stack](../../stack/basic/README.md)
 
 ## Instructions
 
@@ -20,7 +20,7 @@ them:
 - Linked list
 - Two Stacks
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/queue/basic/solution.kt b/src/test/kotlin/com/igorwojda/queue/basic/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/queue/basic/solution.kt
rename to src/test/kotlin/com/igorwojda/queue/basic/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/queue/combine/challenge.kt b/src/test/kotlin/com/igorwojda/queue/combine/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/queue/combine/challenge.kt
rename to src/test/kotlin/com/igorwojda/queue/combine/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/queue/combine/readme.md b/src/test/kotlin/com/igorwojda/queue/combine/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/queue/combine/readme.md
rename to src/test/kotlin/com/igorwojda/queue/combine/README.md
index 3b7d4a01..b2aa2192 100644
--- a/src/test/kotlin/com/igorwojda/queue/combine/readme.md
+++ b/src/test/kotlin/com/igorwojda/queue/combine/README.md
@@ -7,7 +7,7 @@ contain the content of the two queues. The function should handle queues of diff
 into the new one. Take into consideration the fact that both queues may be of different length. IntQueue can only expose
 `add`, `remove`, and `peek` methods to external clients.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/queue/combine/solution.kt b/src/test/kotlin/com/igorwojda/queue/combine/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/queue/combine/solution.kt
rename to src/test/kotlin/com/igorwojda/queue/combine/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/range/containsrange/challenge.kt b/src/test/kotlin/com/igorwojda/range/containsrange/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/range/containsrange/challenge.kt
rename to src/test/kotlin/com/igorwojda/range/containsrange/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/range/containsrange/readme.md b/src/test/kotlin/com/igorwojda/range/containsrange/README.md
similarity index 84%
rename from src/test/kotlin/com/igorwojda/range/containsrange/readme.md
rename to src/test/kotlin/com/igorwojda/range/containsrange/README.md
index 0328b4bc..058432f8 100644
--- a/src/test/kotlin/com/igorwojda/range/containsrange/readme.md
+++ b/src/test/kotlin/com/igorwojda/range/containsrange/README.md
@@ -4,7 +4,7 @@
 
 Given two [ranges](https://kotlinlang.org/docs/ranges.html) implement a function which checks if range1 contains range2.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/range/containsrange/solution.kt b/src/test/kotlin/com/igorwojda/range/containsrange/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/range/containsrange/solution.kt
rename to src/test/kotlin/com/igorwojda/range/containsrange/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/stack/basic/challenge.kt b/src/test/kotlin/com/igorwojda/stack/basic/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/stack/basic/challenge.kt
rename to src/test/kotlin/com/igorwojda/stack/basic/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/stack/basic/readme.md b/src/test/kotlin/com/igorwojda/stack/basic/README.md
similarity index 94%
rename from src/test/kotlin/com/igorwojda/stack/basic/readme.md
rename to src/test/kotlin/com/igorwojda/stack/basic/README.md
index 0e949ee7..a7755d0a 100644
--- a/src/test/kotlin/com/igorwojda/stack/basic/readme.md
+++ b/src/test/kotlin/com/igorwojda/stack/basic/README.md
@@ -17,7 +17,7 @@ them:
 - List
 - Linked list
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/stack/basic/solution.kt b/src/test/kotlin/com/igorwojda/stack/basic/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/stack/basic/solution.kt
rename to src/test/kotlin/com/igorwojda/stack/basic/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/caesarcipher/challenge.kt b/src/test/kotlin/com/igorwojda/string/caesarcipher/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/caesarcipher/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/caesarcipher/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/caesarcipher/readme.md b/src/test/kotlin/com/igorwojda/string/caesarcipher/README.md
similarity index 92%
rename from src/test/kotlin/com/igorwojda/string/caesarcipher/readme.md
rename to src/test/kotlin/com/igorwojda/string/caesarcipher/README.md
index e35b69c4..f6bda426 100644
--- a/src/test/kotlin/com/igorwojda/string/caesarcipher/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/caesarcipher/README.md
@@ -5,7 +5,7 @@
 Given a string and integer `shift` implement a function which shifts each character in that string by `shift` amount ([cesar cipher](https://cryptii.com/pipes/caesar-cipher)) eg. if shift is `1` then `a` becomes `b`, `c` becomes`d`, `z`
 became `a` etc. Allowed input is string containing only lowercase characters from alphabet `abcdefghijklmnopqrstuvwxyz`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/caesarcipher/solution.kt b/src/test/kotlin/com/igorwojda/string/caesarcipher/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/caesarcipher/solution.kt
rename to src/test/kotlin/com/igorwojda/string/caesarcipher/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/capitalizesentence/challenge.kt b/src/test/kotlin/com/igorwojda/string/capitalizesentence/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/capitalizesentence/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/capitalizesentence/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/capitalizesentence/readme.md b/src/test/kotlin/com/igorwojda/string/capitalizesentence/README.md
similarity index 83%
rename from src/test/kotlin/com/igorwojda/string/capitalizesentence/readme.md
rename to src/test/kotlin/com/igorwojda/string/capitalizesentence/README.md
index 0b583803..2575d4ba 100644
--- a/src/test/kotlin/com/igorwojda/string/capitalizesentence/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/capitalizesentence/README.md
@@ -4,7 +4,7 @@
 
 Given a string implement a function which capitalizes first letter of every word in that string.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/capitalizesentence/solution.kt b/src/test/kotlin/com/igorwojda/string/capitalizesentence/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/capitalizesentence/solution.kt
rename to src/test/kotlin/com/igorwojda/string/capitalizesentence/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/decapitalizeconst/challenge.kt b/src/test/kotlin/com/igorwojda/string/decapitalizeconst/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/decapitalizeconst/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/decapitalizeconst/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/decapitalizeconst/readme.md b/src/test/kotlin/com/igorwojda/string/decapitalizeconst/README.md
similarity index 90%
rename from src/test/kotlin/com/igorwojda/string/decapitalizeconst/readme.md
rename to src/test/kotlin/com/igorwojda/string/decapitalizeconst/README.md
index 2000b004..4a4a5cec 100644
--- a/src/test/kotlin/com/igorwojda/string/decapitalizeconst/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/decapitalizeconst/README.md
@@ -9,7 +9,7 @@ converts it into variable name (eg. `fooBar`):
 - convert next words to lowercase, but first character is still uppercase
 - remove all underscore characters
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/decapitalizeconst/solution.kt b/src/test/kotlin/com/igorwojda/string/decapitalizeconst/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/decapitalizeconst/solution.kt
rename to src/test/kotlin/com/igorwojda/string/decapitalizeconst/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/challenge.kt b/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/getduplicatedarguments/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/getduplicatedarguments/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/readme.md b/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/README.md
similarity index 90%
rename from src/test/kotlin/com/igorwojda/string/getduplicatedarguments/readme.md
rename to src/test/kotlin/com/igorwojda/string/getduplicatedarguments/README.md
index 0dff9751..b201b142 100644
--- a/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/README.md
@@ -5,7 +5,7 @@
 Given variable number of arguments (list of strings) checks whether there are any duplicates among the arguments and
 return list of all unique duplicates. If no arguments are passes return empty list.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/solution.kt b/src/test/kotlin/com/igorwojda/string/getduplicatedarguments/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/getduplicatedarguments/solution.kt
rename to src/test/kotlin/com/igorwojda/string/getduplicatedarguments/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/challenge.kt b/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/readme.md b/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/README.md
similarity index 86%
rename from src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/readme.md
rename to src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/README.md
index eccc2173..6d619a6f 100644
--- a/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/README.md
@@ -5,7 +5,7 @@
 Given a string implement a function which returns `true` if string contains at least one repeated character, otherwise
 it returns `false`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
@@ -22,4 +22,4 @@ hasRepeatedCharacter("aabcc") // true
 <details>
 <summary>Hint 1</summary>
 Use frequency counter.
-</details>
\ No newline at end of file
+</details>
diff --git a/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/solution.kt b/src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/solution.kt
rename to src/test/kotlin/com/igorwojda/string/hasrepeatedcharacter/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/isanagram/challenge.kt b/src/test/kotlin/com/igorwojda/string/isanagram/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/isanagram/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/isanagram/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/isanagram/readme.md b/src/test/kotlin/com/igorwojda/string/isanagram/README.md
similarity index 92%
rename from src/test/kotlin/com/igorwojda/string/isanagram/readme.md
rename to src/test/kotlin/com/igorwojda/string/isanagram/README.md
index bf7ef5ad..eb219de0 100644
--- a/src/test/kotlin/com/igorwojda/string/isanagram/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/isanagram/README.md
@@ -6,7 +6,7 @@ Given two strings, implement a function to determine if the second string is an
 word, phrase, or name formed by rearranging the letters of another, such as `cinema`, formed from `iceman`. Only
 consider characters, not spaces or punctuation. Consider capital letters to be the same as lower case.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/isanagram/solution.kt b/src/test/kotlin/com/igorwojda/string/isanagram/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/isanagram/solution.kt
rename to src/test/kotlin/com/igorwojda/string/isanagram/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/challenge.kt b/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/basic/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/basic/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/readme.md b/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/README.md
similarity index 87%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/basic/readme.md
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/basic/README.md
index 55c33f01..179ca805 100644
--- a/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/README.md
@@ -5,7 +5,7 @@
 Given a string, return true if the string is a palindrome or false if it is not. Palindromes are strings that form the
 same word if it is reversed. Include spaces and punctuation in determining if the string is a palindrome.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/solution.kt b/src/test/kotlin/com/igorwojda/string/ispalindrome/basic/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/basic/solution.kt
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/basic/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/challenge.kt b/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/readme.md b/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/README.md
similarity index 85%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/readme.md
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/README.md
index efbec6e7..39670050 100644
--- a/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/README.md
@@ -2,7 +2,7 @@
 
 ## Nice to solve before
 
-- [Palindrome](../basic/readme.md)
+- [Palindrome](../basic/README.md)
 
 ## Instructions
 
@@ -11,7 +11,7 @@ Permutation means that all letters of the string can be used to create a palindr
 
 Palindromes are strings that form the same word if it is reversed.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/solution.kt b/src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/solution.kt
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/permutation/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/challenge.kt b/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/readme.md b/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/README.md
similarity index 86%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/readme.md
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/README.md
index 0761499e..b191da92 100644
--- a/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/README.md
@@ -2,7 +2,7 @@
 
 ## Nice to solve before
 
-- [Palindrome](../basic/readme.md)
+- [Palindrome](../basic/README.md)
 
 ## Instructions
 
@@ -13,7 +13,7 @@ Palindromes are strings that form the same word when reversed (including spaces
 In this exercise one bad character is allowed. The string will be (tolerant) palindrome if after removing one
 character string is a palindrome.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/solution.kt b/src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/solution.kt
rename to src/test/kotlin/com/igorwojda/string/ispalindrome/tolerant/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/issubstring/challenge.kt b/src/test/kotlin/com/igorwojda/string/issubstring/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/issubstring/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/issubstring/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/issubstring/readme.md b/src/test/kotlin/com/igorwojda/string/issubstring/README.md
similarity index 92%
rename from src/test/kotlin/com/igorwojda/string/issubstring/readme.md
rename to src/test/kotlin/com/igorwojda/string/issubstring/README.md
index 713bfdd2..1c0a194f 100644
--- a/src/test/kotlin/com/igorwojda/string/issubstring/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/issubstring/README.md
@@ -8,7 +8,7 @@ Given two strings implement a function which determines whether the characters i
 the characters in the `first` string (check if `second` string exists as continuous/unbroken chain of characters the
 `first` string).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations
 
diff --git a/src/test/kotlin/com/igorwojda/string/issubstring/solution.kt b/src/test/kotlin/com/igorwojda/string/issubstring/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/issubstring/solution.kt
rename to src/test/kotlin/com/igorwojda/string/issubstring/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/longestword/challenge.kt b/src/test/kotlin/com/igorwojda/string/longestword/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/longestword/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/longestword/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/longestword/readme.md b/src/test/kotlin/com/igorwojda/string/longestword/README.md
similarity index 88%
rename from src/test/kotlin/com/igorwojda/string/longestword/readme.md
rename to src/test/kotlin/com/igorwojda/string/longestword/README.md
index a405b48d..47bc8388 100644
--- a/src/test/kotlin/com/igorwojda/string/longestword/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/longestword/README.md
@@ -6,7 +6,7 @@ Given a string implement a function which returns longest word in that string. I
 the same length, return the first longest word from the string. Ignore punctuation. Input string can't be empty or blank
 sering.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/longestword/solution.kt b/src/test/kotlin/com/igorwojda/string/longestword/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/longestword/solution.kt
rename to src/test/kotlin/com/igorwojda/string/longestword/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/maxchar/challenge.kt b/src/test/kotlin/com/igorwojda/string/maxchar/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/maxchar/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/maxchar/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/maxchar/readme.md b/src/test/kotlin/com/igorwojda/string/maxchar/README.md
similarity index 84%
rename from src/test/kotlin/com/igorwojda/string/maxchar/readme.md
rename to src/test/kotlin/com/igorwojda/string/maxchar/README.md
index 126f713b..c24b8fb0 100644
--- a/src/test/kotlin/com/igorwojda/string/maxchar/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/maxchar/README.md
@@ -4,7 +4,7 @@
 
 Given a string implement a function which returns the character that is most commonly used in that string.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
@@ -19,4 +19,4 @@ maxChar("apple 1231111") // "1"
 <details>
 <summary>Hint 1</summary>
 Use frequency counter or multiple pointers pattern.
-</details>
\ No newline at end of file
+</details>
diff --git a/src/test/kotlin/com/igorwojda/string/maxchar/solution.kt b/src/test/kotlin/com/igorwojda/string/maxchar/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/maxchar/solution.kt
rename to src/test/kotlin/com/igorwojda/string/maxchar/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/reverse/challenge.kt b/src/test/kotlin/com/igorwojda/string/reverse/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/reverse/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/reverse/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/reverse/readme.md b/src/test/kotlin/com/igorwojda/string/reverse/README.md
similarity index 85%
rename from src/test/kotlin/com/igorwojda/string/reverse/readme.md
rename to src/test/kotlin/com/igorwojda/string/reverse/README.md
index 51eb4be0..ad7293b0 100644
--- a/src/test/kotlin/com/igorwojda/string/reverse/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/reverse/README.md
@@ -4,7 +4,7 @@
 
 Given a string implement a function which returns a reversed copy of that string.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Limitations:
 
diff --git a/src/test/kotlin/com/igorwojda/string/reverse/solution.kt b/src/test/kotlin/com/igorwojda/string/reverse/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/reverse/solution.kt
rename to src/test/kotlin/com/igorwojda/string/reverse/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/surroundedletter/challenge.kt b/src/test/kotlin/com/igorwojda/string/surroundedletter/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/surroundedletter/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/surroundedletter/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/surroundedletter/readme.md b/src/test/kotlin/com/igorwojda/string/surroundedletter/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/string/surroundedletter/readme.md
rename to src/test/kotlin/com/igorwojda/string/surroundedletter/README.md
index 139a945e..ed3ad630 100644
--- a/src/test/kotlin/com/igorwojda/string/surroundedletter/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/surroundedletter/README.md
@@ -6,7 +6,7 @@ Given a string containing letters and `+` characters implement a function which
 is surrounded by `+` character. There may be more than one `+` character between letters (`+a++b+`) and letters may be
 surrounded by the same `+` character (`+a+b+`).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/surroundedletter/solution.kt b/src/test/kotlin/com/igorwojda/string/surroundedletter/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/surroundedletter/solution.kt
rename to src/test/kotlin/com/igorwojda/string/surroundedletter/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/string/vowels/challenge.kt b/src/test/kotlin/com/igorwojda/string/vowels/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/vowels/challenge.kt
rename to src/test/kotlin/com/igorwojda/string/vowels/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/string/vowels/readme.md b/src/test/kotlin/com/igorwojda/string/vowels/README.md
similarity index 84%
rename from src/test/kotlin/com/igorwojda/string/vowels/readme.md
rename to src/test/kotlin/com/igorwojda/string/vowels/README.md
index 6480c255..1af0bcd4 100644
--- a/src/test/kotlin/com/igorwojda/string/vowels/readme.md
+++ b/src/test/kotlin/com/igorwojda/string/vowels/README.md
@@ -6,7 +6,7 @@ Given string implement a function, which returns the number of vowels used in a
 , `e` `i`, `o`, `u` and
 `y`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/string/vowels/solution.kt b/src/test/kotlin/com/igorwojda/string/vowels/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/string/vowels/solution.kt
rename to src/test/kotlin/com/igorwojda/string/vowels/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/binarysearchtree/challenge.kt b/src/test/kotlin/com/igorwojda/tree/binarysearchtree/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/binarysearchtree/challenge.kt
rename to src/test/kotlin/com/igorwojda/tree/binarysearchtree/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/binarysearchtree/readme.md b/src/test/kotlin/com/igorwojda/tree/binarysearchtree/README.md
similarity index 87%
rename from src/test/kotlin/com/igorwojda/tree/binarysearchtree/readme.md
rename to src/test/kotlin/com/igorwojda/tree/binarysearchtree/README.md
index 67145745..a40c5ebe 100644
--- a/src/test/kotlin/com/igorwojda/tree/binarysearchtree/readme.md
+++ b/src/test/kotlin/com/igorwojda/tree/binarysearchtree/README.md
@@ -4,7 +4,7 @@
 
 Implement [binary search tree (BST)](https://en.wikipedia.org/wiki/Binary_search_tree).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/tree/binarysearchtree/solution.kt b/src/test/kotlin/com/igorwojda/tree/binarysearchtree/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/binarysearchtree/solution.kt
rename to src/test/kotlin/com/igorwojda/tree/binarysearchtree/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/binarytree/insert/challenge.kt b/src/test/kotlin/com/igorwojda/tree/binarytree/insert/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/binarytree/insert/challenge.kt
rename to src/test/kotlin/com/igorwojda/tree/binarytree/insert/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/binarytree/insert/readme.md b/src/test/kotlin/com/igorwojda/tree/binarytree/insert/README.md
similarity index 95%
rename from src/test/kotlin/com/igorwojda/tree/binarytree/insert/readme.md
rename to src/test/kotlin/com/igorwojda/tree/binarytree/insert/README.md
index 6459520d..7bba4a8c 100644
--- a/src/test/kotlin/com/igorwojda/tree/binarytree/insert/readme.md
+++ b/src/test/kotlin/com/igorwojda/tree/binarytree/insert/README.md
@@ -15,7 +15,7 @@ Requirements that are always true for any given node in `Binary Search Tree`:
 - left node value is also a valid  BST
 - right node value is also a valid BST
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/tree/binarytree/insert/solution.kt b/src/test/kotlin/com/igorwojda/tree/binarytree/insert/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/binarytree/insert/solution.kt
rename to src/test/kotlin/com/igorwojda/tree/binarytree/insert/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/binarytree/validate/challenge.kt b/src/test/kotlin/com/igorwojda/tree/binarytree/validate/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/binarytree/validate/challenge.kt
rename to src/test/kotlin/com/igorwojda/tree/binarytree/validate/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/binarytree/validate/readme.md b/src/test/kotlin/com/igorwojda/tree/binarytree/validate/README.md
similarity index 94%
rename from src/test/kotlin/com/igorwojda/tree/binarytree/validate/readme.md
rename to src/test/kotlin/com/igorwojda/tree/binarytree/validate/README.md
index 75095d09..c8644f6e 100644
--- a/src/test/kotlin/com/igorwojda/tree/binarytree/validate/readme.md
+++ b/src/test/kotlin/com/igorwojda/tree/binarytree/validate/README.md
@@ -16,7 +16,7 @@ Requirements that are always true for any given node in `Binary Search Tree`:
 - left node value is also a valid  BST
 - right node value is also a valid BST
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/tree/binarytree/validate/solution.kt b/src/test/kotlin/com/igorwojda/tree/binarytree/validate/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/binarytree/validate/solution.kt
rename to src/test/kotlin/com/igorwojda/tree/binarytree/validate/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/challenge.kt b/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/classic/levelwidth/challenge.kt
rename to src/test/kotlin/com/igorwojda/tree/classic/levelwidth/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/readme.md b/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/README.md
similarity index 73%
rename from src/test/kotlin/com/igorwojda/tree/classic/levelwidth/readme.md
rename to src/test/kotlin/com/igorwojda/tree/classic/levelwidth/README.md
index 76fee5d1..93ad769d 100644
--- a/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/readme.md
+++ b/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/README.md
@@ -2,13 +2,13 @@
 
 ## Nice to solve before
 
-[Tree traversal](../traversal/readme.md)
+[Tree traversal](../traversal/README.md)
 
 ## Instructions
 
 Given the root node of a tree, return an list where each element is the width of the tree at each level.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/solution.kt b/src/test/kotlin/com/igorwojda/tree/classic/levelwidth/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/classic/levelwidth/solution.kt
rename to src/test/kotlin/com/igorwojda/tree/classic/levelwidth/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/classic/traversal/challenge.kt b/src/test/kotlin/com/igorwojda/tree/classic/traversal/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/classic/traversal/challenge.kt
rename to src/test/kotlin/com/igorwojda/tree/classic/traversal/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md b/src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md
similarity index 98%
rename from src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md
rename to src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md
index 88fa7e99..f8fd5270 100644
--- a/src/test/kotlin/com/igorwojda/tree/classic/traversal/readme.md
+++ b/src/test/kotlin/com/igorwojda/tree/classic/traversal/README.md
@@ -2,7 +2,7 @@
 
 ## Nice to solve before
 
-[Queue](../../../queue/basic/readme.md)
+[Queue](../../../queue/basic/README.md)
 
 ## Instructions
 
diff --git a/src/test/kotlin/com/igorwojda/tree/classic/traversal/solution.kt b/src/test/kotlin/com/igorwojda/tree/classic/traversal/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/classic/traversal/solution.kt
rename to src/test/kotlin/com/igorwojda/tree/classic/traversal/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/challenge.kt b/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/challenge.kt
rename to src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/readme.md b/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/README.md
similarity index 93%
rename from src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/readme.md
rename to src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/README.md
index 141ad23d..391afa7b 100644
--- a/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/readme.md
+++ b/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/README.md
@@ -7,7 +7,7 @@ have from `0` to `2` children. Parent nodes are always larger than child nodes,
 smaller than a parents. Heap always have to be filled from "left side" meaning that we can add children to new level
 only if current level is full (each parent from previous level have two children).
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/solution.kt b/src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/solution.kt
rename to src/test/kotlin/com/igorwojda/tree/heap/maxbinaryheap/Solution.kt
diff --git a/src/test/kotlin/com/igorwojda/various/anycallback/challenge.kt b/src/test/kotlin/com/igorwojda/various/anycallback/Challenge.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/various/anycallback/challenge.kt
rename to src/test/kotlin/com/igorwojda/various/anycallback/Challenge.kt
diff --git a/src/test/kotlin/com/igorwojda/various/anycallback/readme.md b/src/test/kotlin/com/igorwojda/various/anycallback/README.md
similarity index 78%
rename from src/test/kotlin/com/igorwojda/various/anycallback/readme.md
rename to src/test/kotlin/com/igorwojda/various/anycallback/README.md
index 2fada00e..4fe4ed85 100644
--- a/src/test/kotlin/com/igorwojda/various/anycallback/readme.md
+++ b/src/test/kotlin/com/igorwojda/various/anycallback/README.md
@@ -2,15 +2,15 @@
 
 ## Nice to solve before
 
-- [Count down](../../integer/countdown/readme.md)
-- [Get odd](../../integer/getodd/readme.md)
+- [Count down](../../integer/countdown/README.md)
+- [Get odd](../../integer/getodd/README.md)
 
 ## Instructions
 
 Given list of integers and callback implement a **recursive** function which returns `true` if simple value in the list
 passed to callback returns `true`, otherwise return `false`.
 
-[challenge](challenge.kt) | [solution](solution.kt)
+[Challenge](Challenge.kt) | [Solution](Solution.kt)
 
 ## Examples
 
diff --git a/src/test/kotlin/com/igorwojda/various/anycallback/solution.kt b/src/test/kotlin/com/igorwojda/various/anycallback/Solution.kt
similarity index 100%
rename from src/test/kotlin/com/igorwojda/various/anycallback/solution.kt
rename to src/test/kotlin/com/igorwojda/various/anycallback/Solution.kt