# https://leetcode.com/problems/number-complement
class Solution:
    def findComplement(self, num: int) -> int:
        def bit_length(num):
            if num == 0:
                return 1
            return len(bin(num)) - 2 
        width = bit_length(num)
        inverted = ~num
        mask = (1 << width) - 1
        result = inverted & mask
        return result