Given an array of integers, every element appearstwiceexcept for one. Find that single one.

Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

int singleNumber(int* nums, int numsSize) {
    int sum=0;
    for(int i=0;i<numsSize;i++)
        sum ^= *(nums+i);
    return sum;
}