Leetcode 136 Single Number

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?

Solution 1: simple bit manipulation .

 public class Solution {  
   public int singleNumber(int[] nums) {  
     int res=0;  
     for (int x: nums) res^=x;  
     return res;  
   }  
 }