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 ret = A[0];
for(int i=1;i<n;++i){
ret = ret ^ A[i];
}
return ret;
}
};