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(int A[], int n) {
        int rtv = 0;

		for(int i = 0; i < n; ++i)
			rtv ^= A[i];

		return rtv;
    }
};