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.

本题很简单，就是寻找额外添加的元素，其实使用Map计数统计即可，

下面是C++的做法，

直接统计然后计数即可

代码如下：

#include <iostream>
#include <vector>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <stack>
#include <string>
#include <climits>
#include <algorithm>
#include <sstream>
#include <functional>
#include <bitset>
#include <numeric>
#include <cmath>
#include <regex>

using namespace std;


class Solution 
{
public:
    char findTheDifference(string s, string t)
    {
        vector<int> count1(26, 0);
        vector<int> count2(26, 0);
        for (char c : s)
            count1[c - 'a']++;
        for (char c : t)
            count2[c - 'a']++;
        for (int i = 0; i < 26; i++)
        {
            if (count1[i] != count2[i])
                return (char)(i + 'a');
        }
        return 0;
    }
};