LeetCode: Find the Difference

ASCII就只有256位，用一个array就可以了

 1 public class Solution {
 2     public char findTheDifference(String s, String t) {
 3         int[] sNum = new int[256];
 4         int[] tNum = new int[256];
 5         for (int i = 0; i < sNum.length; i++) {
 6             sNum[i] = 0;
 7             tNum[i] = 0;
 8         }
 9         for (int i = 0; i < s.length(); i++) {
10             sNum[(int)s.charAt(i)]++;
11         }
12         for (int i = 0; i < t.length(); i++) {
13             tNum[(int)t.charAt(i)]++;
14         }
15         for (int i = 0; i < 256; i++) {
16             if (sNum[i] != tNum[i]) return (char)i;
17         }
18         return '.';
19     }
20 }