Number of Steps to Reduce a Number to Zero.py

class Solution:
    """
    Time:   O(log(n))
    Memory: O(log(n))
    """

    def numberOfSteps(self, num: int) -> int:
        if num == 0:
            return 0
        return 1 + self.numberOfSteps(num - 1 if num & 1 else num >> 1)


class Solution:
    """
    Time:   O(log(n))
    Memory: O(1)
    """

    def numberOfSteps(self, num: int) -> int:
        steps = 0

        while num != 0:
            steps += 1
            if num & 1:
                num -= 1
            else:
                num >>= 1

        return steps


class Solution:
    """
    Time:   O(1)
    Memory: O(1)
    """

    def numberOfSteps(self, num: int) -> int:
        if num == 0:
            return 0
        return num.bit_length() - 1 + num.bit_count()