136. Single Number

题目：

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?

链接： http://leetcode.com/problems/single-number/

题解：

位运算，用异或处理掉出现两次的数字即可。

Time Complexity - O(n)， Space Complexity - O(1)。

public class Solution {

    public int singleNumber(int[] A) {

        int result = 0;

        

        for(int i : A){

            result ^= i;

        }

        

        return result;

    }

}

 

测试：