338. Counting Bits

/**
* Problem statement: https://leetcode.com/problems/backspace-string-compare/
*
* Not a super-efficient solution. There are tricks to do bit-counting that would make this much faster
* (obviating the need to iterate over each bit in the binary string).
*/

/**
 * @param {number} n
 * @return {number[]}
 */
var countBits = function(n) {
    let num = 0;
    const arr = [];
    while (num <= n) {
        arr.push(getOnes(num));
        num += 1;
    }
    return arr;
}

function getOnes(num) {
    const binStr = num.toString(2);
    let count = 0;
    for (let i = 0; i < binStr.length; i++) {
        if (binStr[i] == 1) count += 1;
    }
    return count;
}