Hamming Distance

Posted 2020-10-29 jiadyang

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.

Given two integers x and y, calculate the Hamming distance.

Note:
0 ≤ x, y < 231.

Example:

Input: x = 1, y = 4

Output: 2

Explanation:
1   (0 0 0 1)
4   (0 1 0 0)
       ↑   ↑

The above arrows point to positions where the corresponding bits are different.

这种题真的会有各种技巧，先上个自己写的：

 1 class Solution {
 2 public:
 3     int hammingDistance(int x, int y) 
 4     {
 5         int z = x ^ y;
 6         int res = 0;
 7         while (z != 0)
 8         {
 9             int mod = z % 2;
10             res += mod;
11             z >>= 1;
12         }
13         return res;
14     }
15 };

贴一个优化过的：

 1 class Solution {
 2 public:
 3     int hammingDistance(int x, int y) {
 4         int z = x^y;
 5         int count = 0;
 6         while(z){
 7             count += z&1;
 8             z >>= 1;
 9         }
10         return count;
11     }
12 };