[leedcode 191] Number of 1 Bits

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.

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