191. Number of 1 Bits

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.

Solution

public class Solution {
     public int hammingWeight(int n) {
        int result = 0;
        for (int i = 0; i <= 31; i++) {
            if ((n >>> i & 0x1) == 1) result ++;
        }

        return result;
    }

}