number-complement_476.py

# The complement of an integer is the integer you get when
# you flip all the 0's to 1's and all the 1's to 0's in its binary representation.

# For example, The integer 5 is "101" in binary and its complement is "010" which is the integer 2.
# Given an integer num, return its complement.

# Example 1:

# Input: num = 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: num = 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.
# ---------------------------------------Runtime 46 ms Beats 61.33% Memory 16.2 MB Beats 94.83%---------------------------------------

# Time complexity O(n)


class Solution:
    def findComplement(self, num: int) -> int:
        bins: list = list(bin(num)[2:])
        for i, v in enumerate(bins):
            if v == "0":
                bins[i] = "1"
            else:
                bins[i] = "0"
        return int("".join(bins), 2)


# Solution @xhon9


class Solution:
    def findComplement(self, num: int) -> int:
        return num ^ (2 ** (len(bin(num)[2:])) - 1)