Arrays

1. Given two numbers in form of array add them - ArrayAddition.java
2. Given stock prices for number of days BuySellStockProfit.java

• Buy sell stock once to maximize profit
• Buy sell stocks any number of times to maximum profit

3. Given an array of elements check if elements in the array are consecutive or not. - CheckIfArrayElementsAreConsecutive.java
4. Write a function to determine if array contains duplicate elements within k distance from each other - DuplicateWithinkIndices.java
5. Given an array and a number k < n, find all elements occurring more than n by k times - FindElementsOccurringNByKTimesTetris.java
6. Given a list of gas stations and amount of fuel they have, find a tour which travels all gas stations - GasStationCircle.java
7. Given an unordered array of positive integers, create an algorithm that makes sure no group of integers of size bigger than M have the same integers - GroupElementsInSizeM.java
8. Given an array find an increasing subsequence of length 3 which has maximum product - IncreasingSubsequnceOfLength3WithMaxProduct.java
9. Given an array find maximum circular contiguous sum - KadaneWrapArray.java
10. kth largest element in an unsorted array using quick select - KthElementInArray.java
11. kth largest element in two sorted array - KthLargestInTwoSortedArray.java
12. Print next greater element for every element in array - LargerElementOnRight.java
13. Given an array of 0s and 1s find the largest subarray with equal number of 0s and 1s - LargestSubArrayWithEqual0sAnd1s.java
14. Longest increasing subsequence in an array with O(NlogN) time complexity - LongestIncreasingSubSequenceOlogNMethod.java
15. Given an array maximize i - j such that a[i] > a[j] - MaximumIminusJSuchThatAiGTAj.java
16. Given an array, find maximum of all subarrays of size k - MaximumOfSubarrayOfSizeK.java
17. Given an array of positive and negative numbers, find a subarray which has maximum product - MaxProductSubarray.java maxproductsubarray.py
18. Given an array of size n, the array contains numbers in range from 0 to k-1 where k is a positive integer and k <= n. Find the maximum repeating number in this array - MaxRepeatingNumber.java
19. Given an array and two numbers, find minimum distance between these numbers. There could duplicates of these numbers in array - MinimumDistanceBetweenTwoNumbers.java
20. Find minimum length unsorted subarray, sorting which makes entire array sorted - MinimumSortedWhichSortsEntireArray.java
21. Given array of 0 and non zero numbers, move all 0s to the end in O(n) time - MoveAllZerosToEnd.java
22. Given an array, return a new array which has multiplication of all elements except own index - MultiplyAllFieldsExceptOwnPosition.java
23. Given an unsorted array, find total number of triangles formed taking 3 elements of this array - NumberOfTrianglesInUnsortedArray.java numberoftrianglesunsortedarray.py
24. Given an array with first negative and then positive numbers, position negative and positive numbers alternately - PositiveAndNegativeNumberAlternatively.java
25. Given an array arr[] of size n where every element is in range from 0 to n-1. Rearrange the given array so that arr[i] becomes arr[arr[i]] in O(n) time and O(1) space - RearrangeSuchThatArriBecomesArrArri.java
26. Given an array with elements in range of 0 to n-1, one number is repeated and one number is missing. Find both the numbers - RepeatingAndMissingNumber.java
27. Stable marriage problem - StableMarriageProblem.java
28. Given an unsorted array of nonnegative numbers , find a contiguous subarray with given sum - SubarrayWithGivenSum.java
29. Given an array, find triplet which sums to a given value - https://github.com/mission-peace/interview/blob/master/src/com/interview/array/TripletInArray.java
30. Given a set of n integers, divide the set in two subsets of n/2 sizes each such that the difference of the sum of two subsets is as minimum as possible - TugOfWar.java
31. Given an unsorted array convert it into a < b > c < d > e < f > g fashion - ConvertAnArrayIntoDecreaseIncreaseFashion.java
32. Given multiple sorted lists, sort them into one list - ChunkMerge.java
33. Given an array which represents bars how much rain water will be trapped - TrappingWater.java
34. Print nth number of count sequence. Sequence is like 1 11 21 1211 111221 and so on. NthElementOfCountNumberSequence.java
35. Given 2 arrays of same length consisting of 0s and 1s find max span i,j in two arrays such that sum b/w i to j is same. LongestSameSumSpan.java longestsamesumspan.py
36. Count number of inversions where i < j < k and input[i] > input[j] > input[k] in array. CountInversionOfSize3.java countinversionofsize3.py
37. Given an array of unique integers and total, find all triplets whose sum is less than total. TripletSumLessThanTotal.java tripletsumlessthantotal.py
38. Given array of 0s and 1s and maximum flip allowed from 0 to 1, find maximum number of consecutive 1s you can have in array. Flip0sMaximum1s.java flip0smaximum1s.py
39. Given two arrays, arrange elements of first element by values in second array. ReorderArrayByIndex.java reorderarraybyindex.py
40. Given an array find which rotation will give max sum of i*arr[i] - RotationWithMaxSum.java rotationwithmaxsum.py
41. Zig zag arrangement of array. ZigZagArrangement.java zigzagarrangement.py
42. Rearrange array with elements in range 0 to n-1 such that arr[i] = j becomes arr[j] = i. RearrangeArrayPerIndex.java rearrangearrayperindex.py
43. Given sorted array of positive integers find smallest positive integer not represented by sum of some subset of this array. SmallestIntegerNotRepresentedBySubsetSum.java smallestintegernotrepresentedbysubsetsum.py
44. Arrange positive and negative numbers alternatively maintaining order in input array. PositiveAndNegativeNumberAlternativelyMaintainingOrder.java positiveandnegativealternativelymaintainingorder.py
45. Given two sorted arrays find max sum path from start of any array to end of any array. Switch only happens at common array element. MaximumSumPathTwoArrays.java maximumsumpathtwoarrays.py
46. Find common elements in 3 sorted array. CommonThreeSortedArray.java commonthreesortedarray.py
47. Generate minimum number from give sequence of D and I where D indicates decrease and I indicates increase.[MinimumNumberFromSequence.java] (https://github.com/mission-peace/interview/blob/master/src/com/interview/array/MinimumNumberFromSequence.java)
48. Count smaller numbers on right side of every element in given array - CountSmallerOnRight.java
49. Find max array created by picking k elements from array1 and array2 by maintaining order in both the arrays - MaxNumberFromTwoArray
50. Find duplicate in array of size n + 1 with elements from 1 to n in O(1) space - DuplicateNumberDetection.java
51. Shortest palindrome from a string - ShortestPalindrome.java
52. Find if there exists an increasing subsequence of length 3 or increasing triplet -IncreasingTripletSubsequence.java
53. Given an unsorted array find maximum gap between consecutive element in sorted array - MaximumGap.java
54. Find longest consecutive subsequence in an unsorted array - LongestConsecutiveSubsequence.java
55. Wiggle sort - WiggleSort.java
56. Best meeting point from bunch of people - BestMeetingPoint.java
57. Given an array of positive number arrange it in max min fashion - MaximumMinimumArrangement.java
58. Given a string find if it can form additive number - AdditiveNumber.java
59. Minimum number of meeting rooms needed to schedule array of meetings - MeetingRooms.java
60. Four sum in array equal to given target - FourSum.java
61. Determine if you can reach end of array. You can jump as much as value at every position of array - JumpGame.java
62. Given a sorted array of integers nums and integer values a, b and c. Apply a function of the form f(x) = ax2 + bx + c to each element x in the array - SortedArrayTransformation.java
63. Find missing ranges in sorted array - MissingRanges.java
64. Given a sorted integer array without duplicates, return the summary of its ranges - SummaryRanges.java