LeetCode 136: Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

此题和389题如出一辙：
如果存在相同的数，异或一定会为0，剩下的就是那个单数

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