LeetCode 389 Find the Difference

Problem:

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.

Summary:

s，t均为小写字母组成的string。s为原始string，t为s中元素打乱顺序后随机添加一位所得。

求随机添加的字母。

Analysis:

思想同 LeetCode 136 Single Number

class Solution {
public:
    char findTheDifference(string s, string t) {
        int len  = s.size(), res = 0;
        
        for (int i = 0; i < len; i++) {
            res ^= (s[i]- 'a');
        }
        
        for (int i = 0; i < len + 1; i++) {
            res ^= (t[i]- 'a');
        }
        
        return res + 'a';
    }
};