文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

Find the Difference

2. Solution

• Version 1

class Solution {
public:
    char findTheDifference(string s, string t) {
        unordered_map<char, int> s_map;
        unordered_map<char, int> t_map;
        for(char ch: s) {
            s_map[ch]++;
        }
        for(char ch: t) {
            t_map[ch]++;
        }
        for(auto temp: t_map) {
            if(s_map[temp.first] < temp.second) {
                return temp.first;
            }
        }
    }
};

• Version 2

class Solution {
public:
    char findTheDifference(string s, string t) {
        char c = 0;
        for(char ch: s) {
            c ^= ch;
        }
        for(char ch: t) {
            c ^= ch;
        }
        return c;
    }
};

Reference

1. https://leetcode.com/problems/find-the-difference/description/