Add 53.. tough one

src/ex/q053.clj

@@ -0,0 +1,15 @@
+;; https://4clojure.oxal.org/#/problem/053
+
+(ns ex.q053)
+
+(defn ans
+  "Problem 53, Longest Increasing Sub-Seq"
+  [coll]
+  (->> coll
+       (partition 2 1) ;; create overlapping pairs
+       (partition-by #(= (inc (first %)) (second %))) ;; partition by increasing pairs
+       (filter #(= (inc (ffirst %)) (second (first %)))) ;; drop violations
+       (sort-by count)
+       last ;; grab longest sequence
+       (reduce concat)
+       dedupe)) ;; remove overlapping elements

test/ex/q053_test.clj

@@ -0,0 +1,12 @@
+;; https://4clojure.oxal.org/#/problem/053
+
+(ns ex.q053-test
+  (:require [clojure.test :as t]
+            [ex.q053 :as sut]))
+
+(t/deftest test-q53
+  (t/testing "Problem 53, Longest Increasing Sub-Seq"
+    (t/is (= [0 1 2 3] (sut/ans [1 0 1 2 3 0 4 5])))
+    (t/is (= [5 6] (sut/ans [5 6 1 3 2 7])))
+    (t/is (= [3 4 5] (sut/ans [2 3 3 4 5])))
+    (t/is (= [] (sut/ans [7 6 5 4])))))