“The best thing about a boolean is even if you are wrong, you are only off by a bit.”
~Bryan

Day 4 of the May LeetCoding Challenge by Leetcode

When you start out with competitive coding, you may tend to set unreasonable goals for yourself. The problem with this is that it cannot be achieved overnight. Start with the basics, you may take time to understand stuff, but that’s okay! Work on a few problems daily and you are sure to see the difference. And practice makes perfect, right?

Problem definition: Number Complement

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.
• This question is the same as 1009

Sample Testcase

Testcase 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.

Testcase 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.

I highly encourage you to attempt this problem on your own before looking at my solution.

Approach

The NOT bitwise operator in could be one approach to solving the problem. To implement everything from scrath you can convert the decimal to binary, complement it and return the decimal of the binary number obtained!

Solution

class Solution(object):
    def findComplement(self, num):
        """
        :type num: int
        :rtype: int
        """
        ones = ""
        binary = bin(num)
        binary = binary.replace('0b','')
        for i in range(0,len(binary)):
            if(binary[i]=='0'):
                ones = ones + '1'
            else:
                ones = ones + '0'
        return int(ones,2)   

Submission Details

Total test cases passed: 149 / 149
Runtime: 20 ms
Memory Usage: 12.6 MB

Note: This submission was better than 43.98% of Python3 solutions in terms of runtime. Think hard and try to come up with a solution that is more optimal! 🌚
You could use Bitwise operators as an alternative!

I would really recommend you to explore this side of the Computer Science and tune in to the journey of competitive programming to write better, cleaner, efficient and optimal code! 😀

If you have a better approach to this problem, or for any other queries feel free to reach out to me! 😇