Added consecutive-strings.rb

Author: malachispencer

ruby/6kyu/consecutive-strings.rb

@@ -0,0 +1,26 @@
+=begin
+Codewars. 30/04/20. 'Consecutive strings'. 6kyu. Here we create a method that 
+takes an array of strings and returns the longest possible string that can be 
+derived by combining k consecutive strings in the array. In the case of there 
+being multiple matches, return the first. If the array is empty, or k is greater 
+than the array length, or k is less than 1, return an empty string. Here is the 
+solution I developed to solve the challenge.
+1) We define our method longest_k_consec_ms, which takes 2 arguments, arr, an
+ array of strings, and k, the amount of consecutive strings that the longest
+ possible string should consist of.
+2) We handle our error checking and return an empty string if the array is
+ empty, or k is less than 1, or k is greater than the array size.
+3) We call the each_cons method with k passed in as its argument, so now we
+ have an array of arrays where each sub-array is k consecutive strings from
+ the original array.
+4) We map over the array of arrays and join each sub-array. So now we have an
+ array of combined k-consecutive strings.
+5) We call the max_by method with the length method passed in as an argument,
+ which returns longest (combined k-consecutive) string. If there are more
+ than 1 string with the max value, the first is returned.
+=end
+
+def longest_k_consec_ms(arr, k)
+ return "" if arr.empty? || k < 1 || k > arr.size
+ arr.each_cons(k).map(&:join).max_by(&:length)
+end