31(May) Swap two nibbles in a byte

31. Swap Two Nibbles in a Byte

The problem can be found at the following link: Question Link

Problem Description

Given a number n, your task is to swap the two nibbles and find the resulting number.

A nibble is a four-bit aggregation, or half an octet. There are two nibbles in a byte. For example, the decimal number 150 is represented as 10010110 in an 8-bit byte. This byte can be divided into two nibbles: 1001 and 0110.

Example:

Input:

n = 100

Output:

70

Explanation: 100 in binary is 01100100, two nibbles are (0110) and (0100). If we swap the two nibbles, we get 01000110 which is 70 in decimal.

Approach

To solve this problem, follow these steps:

1. Masking and Shifting:

   • Extract the right nibble (the last 4 bits) by performing a bitwise AND with 0x0F and left shift it by 4 positions.

   • Extract the left nibble (the first 4 bits) by performing a bitwise AND with 0xF0 and right shift it by 4 positions.

2. Combine Nibbles:

   • Combine the two extracted nibbles using a bitwise OR operation.

3. Return Result:

   • Return the result of the combination which is the integer value after swapping the nibbles.

Time and Auxiliary Space Complexity

• Expected Time Complexity: O(1), as we perform a constant number of operations regardless of the input size.

• Expected Auxiliary Space Complexity: O(1), as we only use a constant amount of additional space.

Code

C++

class Solution {
public:
    int swapNibbles(int n) {
        int rn = (n & 0xF0) >> 4;
        int ln = (n & 0x0F) << 4;
        return rn | ln;
    }
};

Java

class Solution {
    static int swapNibbles(int n) {
        int rn = (n & 0xF0) >> 4;
        int ln = (n & 0x0F) << 4;
        return rn | ln;
    }
}

Python

class Solution:
    def swapNibbles(self, n: int) -> int:
        rn = (n & 0xF0) >> 4
        ln = (n & 0x0F) << 4
        return rn | ln

Contribution and Support

For discussions, questions, or doubts related to this solution, feel free to connect on LinkedIn: Any Questions. Let’s make this learning journey more collaborative!

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