/**
 * @param {number} num
 * @return {number[]}
 */
const countBits = num => {
  const result = [0];

  while (result.length <= num) {
    const len = result.length;

    for (let i = 0; i < len; i++) {
      result.push(result[i] + 1);

      if (result.length > num) break;
    }
  }

  return result;
};