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.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.


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

public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int ret = 0;
        for (int i = 0; i < 32; i++) {
            ret += (n & 1);
            n = n >> 1;
        }
        return ret;
    }
}