136. Single Number (Bit)

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 result = A[0];
        int i = 1;
        while(i<n)
        {
            result = A[i] ^ result; //异或，相同为0 不同为1
            i++;
        }
        return result;
    }
};