0191. Number of 1 Bits.js

// Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight).
//
// Example 1:
//
// Input: 11
// Output: 3
// Explanation: Integer 11 has binary representation 00000000000000000000000000001011
//
// Example 2:
//
// Input: 128
// Output: 1
// Explanation: Integer 128 has binary representation 00000000000000000000000010000000

/**
 * @param {number} n - a positive integer
 * @return {number}
 */

// 1)
const hammingWeight1 = (n) => {
  return n.toString(2).split('0').join('').length;
};

// 2)
const hammingWeight = (n) => {
  let w = 0;
  for (let c of n.toString(2)) {
    if (c === '1') w++;
  }
  return w;
};