Given two strings s and t which consist of only lowercase letters.

String t is generated by random shuffling string s and then add one more letter at a random position.

Find the letter that was added in t.

class Solution {
    public char findTheDifference(String s, String t) {
        int[] count = new int[26];
        for(int i = 0; i < s.length(); i++) {
            count[s.charAt(i) - 'a']++;
        }

        for(int i = 0; i < t.length(); i++) {
            count[t.charAt(i) - 'a']--;
            if(count[t.charAt(i) - 'a'] == -1)
                return t.charAt(i);
        }

        return ' ';
    }
}