[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;
}
}