LeetCode 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.

hash表

public char findTheDifference(String s, String t) {
        char[] sch = s.toCharArray();
        char[] tch = t.toCharArray();
        int[] hashs = new int[256];


        for(char ch : sch) hashs[ch]++;
        for (char ch : tch) {
            if(hashs[ch]-- <= 0) return ch;
        }
        return ' ';


    }