Write count_ones(n) that returns how many 1 bits appear in the binary form of the non-negative integer n. Solve it with a loop and arithmetic (% 2 and // 2) rather than bin().
Examples
Input: n = 13
Output: 3
Explanation: 13 is 1101 in binary.
Input: n = 0
Output: 0
Constraints
0 <= n <= 2**60
Goals
- Break a number down by repeatedly dividing by 2
- Count the remainders that equal 1