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?
在《编程之美》里面见过，很巧妙的一种异或运算的解决方案。
1 class Solution { 2 public: 3 int singleNumber(vector<int>& nums) { 4 int res = 0; 5 for(int i = 0;i<nums.size();i++){ 6 res = res ^ nums[i]; 7 } 8 return res; 9 } 10 };
原文：http://www.cnblogs.com/suwish/p/5233403.html