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;
     }
 };