LeetCode

Description

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.

Solution

除了最容易想到的暴力法，还可以用n与n-1按位与的方法

python版：

class Solution(object):
    def hammingDistance(self, x, y):
        """
        :type x: int
        :type y: int
        :rtype: int
        """
        xor = x ^ y
        count = 0
        while (xor != 0):
            xor = xor & (xor - 1)
            count = count + 1
        
        return count

cpp版：

class Solution {
public:
    int hammingDistance(int x, int y)
    {
        int xor_diff = x ^ y;
        int count = 0;
        while (xor_diff != 0)
        {
            count++;
            xor_diff = xor_diff & (xor_diff-1);
        }
        return count;
    }
};

Reference：

• http://www.cnblogs.com/grandyang/p/6201215.html