260. Single Number III

 1 public class Solution {
 2     public int[] singleNumber(int[] nums) {
 3         // Pass 1 : 
 4         // Get the XOR of the two numbers we need to find
 5         int diff = 0;
 6         for (int num : nums) {
 7             diff ^= num;
 8         }
 9         // Get its last set bit which num1 is diff from num2
10         diff &= -diff;
11 
12         // Pass 2 :
13         int[] rets = {0, 0}; // this array stores the two numbers we will return
14         for (int num : nums)
15         {
16             if ((num & diff) == 0) // the bit is not set
17             {
18                 rets[0] ^= num;
19             }
20             else // the bit is set
21             {
22                 rets[1] ^= num;
23             }
24         }
25         return rets;
26     }
27 }