LeetCode: Reverse Bits

PublishedNovember 23, 2025

•1 min read

Problem:

https://leetcode.com/problems/reverse-bits/description/

Code:

class Solution:
    def reverseBits(self, n: int) -> int:
        bin_num = format(n, '032b')
        rev = bin_num[::-1]
        return int(rev, 2)

Key Points:

Every input number is treated as a 32-bit binary number.
First, convert the number into a 32-bit binary string: format(n, '032b') → ensures leading zeros are included.
Reverse the binary string using slicing: rev = bin_num[::-1]
Convert the reversed binary string back to an integer: int(rev, 2)
This gives the final result where all 32 bits have been flipped in order.
Time: O(32) → effectively constant time.
Space: O(32) → storing the 32-bit string.

#python #python3 #coding #leetcode #hashnode #build-in-public

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