[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?

思考：位运算。

class Solution {

public:

    int singleNumber(int A[], int n) {

        // IMPORTANT: Please reset any member data you declared, as

        // the same Solution instance will be reused for each test case.

        int ret=0;

		while(n--)

		{

			ret^=A[n];

		}

		return ret;

    }

};