/*

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 hammingWeight {

// n is unsigned

public static int hammingWeight(int n) {

int cnt = 0;

String s = Integer.toBinaryString(n);

for (int i = 0; i < s.length(); i++) {

if (s.charAt(i) == '1') {

cnt += 1;

}

}

return cnt;

}

public static int hammingWeight1(int n) {

int cnt = 0;

if (n == 0) {return 0;}

while (n != 0) {

if ((n&1) == 1) {

cnt += 1;

}

n >>>= 1;

}

return cnt;

}

public static void main(String[] args) {

int nWeight = hammingWeight(15);

System.out.println(nWeight);

String x = Integer.toBinaryString(15);

System.out.println(x);

int nWeight1 = hammingWeight1(2);

System.out.println(nWeight1);

}

}