Leetcode 136 Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

Note: Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

找出唯一一个只出现一次的数字。

学异或时的经典题型！

class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int res = 0;
        for(int i = 0; i < nums.size(); i++) res ^= nums[i];
        return res;
    }
};