【LeetCode】 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;
for (int i = 0; i < 32; i++) {
if ((n & 1) == 1) {
res++;
}
n = n >>> 1;
}
return res;
}
}