Swap Without Extra Variable

Given two variables, x and y, swap two variables without using a third variable.

 

Example

Given x = 10, y = 5
Return 15.

思路：考察位运算，异或。 同一个数异或两次还是其本身。

class Solution {
public:
    /**
     * @param x an integer
     * @param y an integer
     * @return nothing
     */
    void swap(int &x, int &y) {
        // Write your code here
        x = x ^ y;
        y = x ^ y;
        x = x ^ y;
    }
};