Number of 1 Bits

Leetcode

題意：

Write a function that takes an unsigned integer and returns the number of 』1' bits it has (also known as the Hamming weight).

For example, the 32-bit integer 』11' has binary representation 00000000000000000000000000001011, so the function should return 3.

解題思路：

public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int count = 0;
        while (n != 0) {
            count++;
            n = n & (n - 1);
        }
        return count;
    }
}