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?

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