radix_sort_demo

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Filename: radix_sort_demo.py
# Version: 1.0.0
# Author: Jeoi Reqi

"""
Description:
    This script demonstrates the Radix Sort algorithm by sorting an array of integers.

Requirements:
    - Python 3.x

Functions:
    - counting_sort(arr, exp):
        Perform counting sort on the array `arr` based on the exponent `exp`.

    - radix_sort(arr):
        Perform radix sort on the given list `arr` using counting_sort as a subroutine.

Usage:
    - Run the script to see the Radix Sort algorithm in action.

Example Output:

                :: RADIX SORTING DEMO ::

        Original array: [170,  45,  75,  90, 802,  24,   2,  66]
        Sorted array:   [  2,  24,  45,  66,  75,  90, 170, 802]

        Radix Sorting Complete!

            Exiting Program...   GoodBye!

Additional Notes:
    - Radix Sort is efficient for sorting integers, especially when the range of numbers is known and limited.
"""

def counting_sort(arr, exp):
    """
    Perform counting sort on the array `arr` based on the exponent `exp`.

    Args:
        arr (list): List of integers to be sorted.
        exp (int): Exponent used to sort elements.

    Returns:
        None. The list `arr` is sorted in place based on the exponent `exp`.
    """
    n = len(arr)
    output = [0] * n
    count = [0] * 10

    for i in range(n):
        index = arr[i] // exp
        count[index % 10] += 1

    for i in range(1, 10):
        count[i] += count[i - 1]

    i = n - 1
    while i >= 0:
        index = arr[i] // exp
        output[count[index % 10] - 1] = arr[i]
        count[index % 10] -= 1
        i -= 1

    for i in range(n):
        arr[i] = output[i]

def radix_sort(arr):
    """
    Perform radix sort on the given list `arr` using counting_sort as a subroutine.

    Args:
        arr (list): List of integers to be sorted in place.

    Returns:
        None. The list `arr` is sorted in place using radix sort.
    """
    max1 = max(arr)
    exp = 1
    while max1 // exp > 0:
        counting_sort(arr, exp)
        exp *= 10

def main():
    """
    Main function to demonstrate radix sort.

    It initializes an example array, sorts it using radix_sort function,
    and prints the original and sorted arrays.
    """
    print("\n\t\t:: RADIX SORTING DEMO ::\n")

    # Example array to sort
    arr = [170, 45, 75, 90, 802, 24, 2, 66]

    # Print the original array
    original_arr_str = "["
    for index, num in enumerate(arr):
        if index == 0:
            original_arr_str += f"{num:3}"  # Add two spaces for single-digit numbers
        else:
            original_arr_str += f", {num:3}" if num >= 10 else f",  {num:2}"  # Add one space for two-digit numbers
    original_arr_str += "]"
    print("Original array:", original_arr_str)

    # Sort the array using radix sort
    radix_sort(arr)

    # Print the sorted array
    sorted_arr_str = "["
    for index, num in enumerate(arr):
        if index == 0:
            sorted_arr_str += f"{num:3}"  # Add two spaces for single-digit numbers
        else:
            sorted_arr_str += f", {num:3}" if num >= 10 else f",  {num:2}"  # Add one space for two-digit numbers
    sorted_arr_str += "]"
    print("Sorted array:  ", sorted_arr_str)

    # Print completion message
    print("\nRadix Sorting Complete!\n\n\tExiting Program...   GoodBye!")

if __name__ == "__main__":
    main()