"""
Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

Note:

    The given integer is guaranteed to fit within the range of a 32-bit signed integer.
    You could assume no leading zero bit in the integer’s binary representation.

Example 1:

Input: 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.

Example 2:

Input: 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.
"""

class Solution(object):
    def findComplement(self, num):
        """
        :type num: int
        :rtype: int
        """
        bitmask = self.find_num_bits(num)
        return ~num & bitmask

    def find_num_bits(self, num):
        bits = 0
        while num != 0:
            num >>= 1
            bits <<= 1
            bits += 1
        return bits

ans = Solution()
for i in range(7):
    print(i, ans.findComplement(i))
