I have an array of strings [abb, bbxxaa].I would like to print all characters that occur equal times in each index so in above case I would print bb because they occur twice in both indexes and a occurs once and twice in first and second index respectively. My approach:Keep track of only the characters in the first index and because we would not need to worry about other letters anyway.So in above case I would keep track of letter a and b and check ifthey occur same time in the next indexes. Can someone suggest a better way if possible or am I on right track? 
Return equal occurrence of char in a list of strings
c;strings