Try to split all the numbers into two groups with each of the target one in different groups. Refer to this link for a nice explanation.
The code is written as follows.
1 class Solution { 2 public: 3 vector<int> singleNumber(vector<int>& nums) { 4 int t = 0, p, first = 0, second = 0; 5 for (int num : nums) t ^= num; 6 for (p = 0; p < 32; p++) 7 if ((t >> p) & 1) break; 8 for (int num : nums) { 9 if ((num >> p) & 1) first ^= num; 10 else second ^= num; 11 } 12 return {first, second}; 13 } 14 };
原文：http://www.cnblogs.com/jcliBlogger/p/4736904.html