136. Single Number

Posted 2020-12-01 zjuhaohaoxuexi

题目描述:

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?

思路：

利用了异或操作的性质：

1，两个相同的数异或的结果为0
2，一个数和0异或的结果为这个数

代码：

 1 class Solution {
 2 public:
 3     int singleNumber(int A[], int n) {
 4 
 5         int result = 0;
 6         for(int i = 0;i < n;i++)
 7         {
 8             result ^= A[i];
 9         }
10         return result;
11         
12     }
13 };