|Given a collection of n strings, there are n! ways to concatenate them into a
single string. Create a class LongestRun that contains method runLength that
takes a String collection as input and returns the length of the longest run
that can be formed by concatenating the strings.
A run is a sequence of adjacent identical characters. For example, "CACAAABBQ" contains a run of 2 B's and a run of 3 A's (as well as four other runs of length 1).
|-||collection contains between 1 and 50 elements inclusive|
|-||each element of collection contains between 1 and 50 characters inclusive|
|-||each element of collection contains only uppercase letters, 'A'-'Z'|