Leetcode: 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?

最简单直白。

class Solution {
public:
    int singleNumber(int A[], int n) {
        int result = 0;
        for (int i = 0; i < n; ++i) {
            result ^= A[i];
        }
        
        return result;
    }
};

=======================第二次=====================

class Solution {public:    int singleNumber(int A[], int n) {        int result = 0;        for (int i = 0; i < n; ++i) {            result ^= A[i];        }                return result;    }};