461.Hamming Distance

Posted on | In

Bit Manipulation

Question

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:

1
2
3
4
5
6
7
8
9
10
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.

My Answer

1
2
3
4
5
6
7
8
9
10
11
class Solution {
    public int hammingDistance(int x, int y) {
        int temp = x^y;
        int res = 0;
        while(temp!=0){
            temp = temp & (temp-1);
            res++;
        }
        return res;
    }
}

Running time: 12ms

Simpler Answer

1
2
3
4
5
class Solution {
    public int hammingDistance(int x, int y) {
        return Integer.bitCount(x ^ y);
    }
}

Running time: 12ms

BitCount

1
2
3
4
5
6
int res=0;
while(num!=0){
    num = num & (num-1);
    res++;
}
// res --> the number of bit 1