Return Words in Repeated Anagram Groups

Given an array of strings words, return every occurrence whose anagram signature appears more than once in the array. For each word, build an anagram signature as a 26-element count of lowercase letters 'a' through 'z'. Character order is ignored, but multiplicity is not: "ab" and "aab" have different signatures even though they contain the same distinct letters. Using only a set of distinct letters would be insufficient for this reason. Return the qualifying words exactly…