2016 Update

Task/Longest-string-challenge/Clojure/longest-string-challenge.clj

@@ -0,0 +1,30 @@
+ns longest-string
+  (:gen-class))
+
+(defn longer [a b]
+  " if a is longer, it returns the characters in a after length b characters have been removed
+    otherwise it returns nil "
+  (if (or (empty? a) (empty? b))
+    (not-empty a)
+    (recur (rest a) (rest b))))
+
+(defn get-input []
+  " Gets the data from standard input as a lazy-sequence of lines (i.e. reads lines as needed by caller
+    Input is terminated by a zero length line (i.e. line with just <CR> "
+  (let [line (read-line)]
+    (if (> (count line) 0)
+      (lazy-seq (cons line (get-input)))
+      nil)))
+
+(defn process []
+  " Returns list of longest lines "
+  (first                                                             ; takes lines from [lines longest]
+    (reduce (fn [[lines longest] x]
+             (cond
+              (longer x longest) [x x]                               ; new longer line
+              (not (longer longest x)) [(str lines "\n" x) longest] ; append x to previous longest
+              :else [lines longest]))                               ; keep previous lines & longest
+            ["" ""] (get-input))))
+
+(println "Input text:")
+(println "Output:\n" (process))