Reverse Bits LeetCode Solution

Last updated on January 20th, 2025 at 11:00 pm

Here, we see a Reverse Bits LeetCode Solution. This Leetcode problem is solved using different approaches in many programming languages, such as C++, Java, JavaScript, Python, etc.

List of all LeetCode Solution

Topics

Bit-Manipulation

Companies

Airbnb, Apple

Level of Question

Easy

Reverse Bits LeetCode Solution

Reverse Bits LeetCode Solution

1. Problem Statement

Reverse bits of a given 32 bits unsigned integer.

Note:

  • Note that in some languages, such as Java, there is no unsigned integer type. In this case, both input and output will be given as a signed integer type. They should not affect your implementation, as the integer’s internal binary representation is the same, whether it is signed or unsigned.
  • In Java, the compiler represents the signed integers using 2’s complement notation. Therefore, in Example 2 above, the input represents the signed integer -3 and the output represents the signed integer -1073741825.
Example 1:
Input: n = 00000010100101000001111010011100
Output:    964176192 (00111001011110000010100101000000)
Explanation: The input binary string 00000010100101000001111010011100 represents the unsigned integer 43261596, so return 964176192 which its binary representation is 00111001011110000010100101000000.

Example 2:
Input: n = 11111111111111111111111111111101
Output:   3221225471 (10111111111111111111111111111111)
Explanation: The input binary string 11111111111111111111111111111101 represents the unsigned integer 4294967293, so return 3221225471 which its binary representation is 10111111111111111111111111111111.

2. Coding Pattern Used in Solution

The coding pattern used in all the provided implementations is Bit Manipulation. This pattern involves performing operations directly on the binary representation of numbers using bitwise operators or binary string manipulations.

3. Code Implementation in Different Languages

3.1 Reverse Bits C++

class Solution {
public:
    uint32_t reverseBits(uint32_t n) {
        uint32_t res = 0;
        for (int i = 0; i < 31; i++) {
            res = (n % 2) + res << 1;
            n >>= 1;
        }
        return res + n % 2;
    }
};

3.2 Reverse Bits Java

public class Solution {
    public int reverseBits(int n) {
        int res=0;
    for(int i=0;i<32;i++){
    	res= ( res << 1 ) | ( n & 1 );         
    	n = n >> 1;                  
    }
    return res;
    }
}

3.3 Reverse Bits JavaScript

var reverseBits = function(n) {
    return parseInt([...`${Number(n).toString(2)}`.padStart(32,0)].reverse().join(''),2)
};

3.4 Reverse Bits Python

class Solution:
    def reverseBits(self, n):
        oribin='{0:032b}'.format(n)
        reversebin=oribin[::-1]
        return int(reversebin,2)

4. Time and Space Complexity

Time ComplexitySpace Complexity
C++O(1)O(1)
JavaO(1)O(1)
JavaScriptO(1)O(1)
PythonO(1)O(1)
  • The C++ and Java implementations are more efficient in terms of space usage as they avoid creating intermediate binary strings.
  • The JavaScript and Python implementations are more concise but use additional space for string manipulation.
  • All implementations have the same time complexity of O(1) due to the fixed number of bits (32).

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