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?
class Solution { public: int singleNumber(int A[], int n) { int ans=A[0]; for(int i=1;i<n;i++) { ans = ans^A[i]; } return ans; } };
原文：http://www.cnblogs.com/code-swan/p/4139690.html