leetcode 389. Find the Difference

发表于 | 分类于

题目

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.

#解法
将s和t中的字符一一异或，可以得到唯一多出来的字符，但这样需要两个指针，所以比较复杂，由于异或具有交换性，所以可以将s中的字符异或之后再异或t中的字符，结果一样。

1
2
3
4
5
6
7
8
9
10
11
class Solution {
public:
    char findTheDifference(string s, string t) {
        char r = 0;
        for(char c : s)
            r ^= c;
        for(char c : t)
            r ^= c;
        return r;
    }
};