LeetCode: Single Number II

这题有点难，网上大神的这段代码太牛了。

 1 class Solution {

 2 public:

 3     int singleNumber(int A[], int n) {

 4         // Note: The Solution object is instantiated only once and is reused by each test case.

 5         int one = 0;

 6         int two = 0;

 7         int three = 0;

 8         for(int i = 0 ; i < n ; i++){

 9             two |= A[i] & one;

10             one = A[i] ^ one;

11             three = ~(one&two);

12             one &= three;

13             two &= three;

14         }

15         return one;

16     }

17 };

这段代码就很好理解

 1 class Solution {

 2 public:

 3     int singleNumber(int A[], int n) {

 4         int ans = 0;

 5         for (int i = 0; i < 32; ++i) {

 6             int count = 0;

 7             for (int j = 0; j < n; ++j) count += (A[j] >> i) & 1;

 8             ans |= ((count % 3 != 0) << i);

 9         }

10         return ans;

11     }

12 };

 C#

 1 public class Solution {

 2     public int SingleNumber(int[] nums) {

 3         int ans = 0;

 4         for (int i = 0; i < 32; i++) {

 5             int count = 0;

 6             for (int j = 0; j < nums.Length; j++) count += (nums[j] >> i) & 1;

 7             ans |= ((count % 3 != 0? 1 : 0) << i);

 8         }

 9         return ans;

10     }

11 }

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