https://leetcode.com/problems/find-the-difference/ public class Solution { public char findTheDifference(String s, String t) { char[] sch = s.toCharArray(); char[] tch = t.toCharArray(); Arrays.sort(sch); Arrays.sort(tch); for (int i=0; i<sch.length; i++) { if (sch[i] != tch[i]) { return tch[i]; } } return tch[tch.length-1]; } }