counting-bits.js

/* Counting Bits

Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n),
ans[i] is the number of 1's in the binary representation of i.

Example 1:
Input: n = 2
Output: [0,1,1]
Explanation:
0 --> 0
1 --> 1
2 --> 10

Example 2:
Input: n = 5
Output: [0,1,1,2,1,2]
Explanation:
0 --> 0
1 --> 1
2 --> 10
3 --> 11
4 --> 100
5 --> 101

Constraints:
    0 <= n <= 105
*/

/**
 * @param {number} n
 * @return {number[]}
 */
 var countBits = function(n) {
    let counts = [0];
    
    if(n === 0){
        return counts;
    }
    
    for(let i = 1; i <= n; i++){
        let curr = i;
        let tempCount = 0;
        
        while(curr > 0){
            let one = curr & 1;
            tempCount += one === 1 ? 1 : 0;        
            curr = curr >>> 1;
        }
    
        counts.push(tempCount);
    }
      
    return counts;
};