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?
异或即可处理,而且,不仅能处理两次的情况,只要出现偶数次,都可以清零。
1 class Solution { 2 public: 3 int singleNumber(int A[], int n) { 4 5 int res = 0; 6 7 for(int i = 0; i<n; i++) 8 { 9 res = res ^ A[i]; 10 } 11 12 return res; 13 } 14 };