Reverse Bits Explained

Problem Statement

Given a 32-bit unsigned integer n, reverse its bits and return the result as an unsigned integer. For example, if the input is 43261596 (binary: 00000010100101000001111010011100), the output is 964176192 (binary: 00111001011110000010100101000000). This problem tests your ability to manipulate individual bits using shifts and bitwise operations to achieve the reversal.

Example

Input: n = 43261596

Output: 964176192

Explanation: The 32-bit binary representation of 43261596 is reversed to produce 964176192.

Code

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

    public static void main(String[] args) {
        Solution sol = new Solution();
        System.out.println(sol.reverseBits(43261596)); // 964176192
    }
}
            

def reverse_bits(n):
    result = 0
    for _ in range(32):
        result <<= 1
        result |= (n & 1)
        n >>= 1
    return result

# Example usage
print(reverse_bits(43261596))  # 964176192
            

function reverseBits(n) {
    let result = 0;
    for (let i = 0; i < 32; i++) {
        result <<= 1;
        result |= (n & 1);
        n >>>= 1;
    }
    return result >>> 0;
}

// Example usage
console.log(reverseBits(43261596)); // 964176192
            

Explanation

• Initialize result to 0 to build the reversed bits.
• For each of the 32 bits:
• Left-shift result by 1 to make space for the next bit.
• Extract the least significant bit of n using n & 1 and OR it into result.
• Right-shift n by 1 to process the next bit.
• Return the final result.

Note