_389.java

package com.fishercoder.solutions;
/**
 * 389. Find the Difference
 *
 * 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.

 Example:

 Input:
 s = "abcd"
 t = "abcde"

 Output:
 e

 Explanation: 'e' is the letter that was added.*/

public class _389 {
    public static class Solution1 {
        public char findTheDifference(String s, String t) {
            int[] counts = new int[128];
            char[] schars = s.toCharArray();
            char[] tchars = t.toCharArray();
            for (int i = 0; i < schars.length; i++) {
                counts[schars[i]]++;
            }
            for (int i = 0; i < tchars.length; i++) {
                counts[tchars[i]]--;
            }
            char result = 'a';
            for (int i = 0; i < 128; i++) {
                if (counts[i] != 0) {
                    result = (char) i;
                }
            }
            return result;
        }
    }
}