PHP Array Exercises : Sort an array of positive integers using the Bead-Sort Algorithm

PHP Array: Exercise-10 with Solution

Write a PHP program to sort an array of positive integers using the Bead-Sort Algorithm.

According to Wikipedia "Bead-sort is a natural sorting algorithm, developed by Joshua J. Arulanandham, Cristian S. Calude and Michael J. Dinneen in 2002. Both digital and analog hardware implementations of bead sort can achieve a sorting time of O(n); however, the implementation of this algorithm tends to be significantly slower in software and can only be used to sort lists of positive integers".

Input array : Array ( [0] => 5 [1] => 3 [2] => 1 [3] => 3 [4] => 8 [5] => 7 [6] => 4 [7] => 1 [8] => 1 [9] => 3 )

Sample Solution:

<?php
// Define a function named 'columns' that transposes a 2D array
function columns($uarr)
{
    $n = $uarr;

    // Check if the array is empty
    if (count($n) == 0)
        return array();
    // Check if the array has only one element
    else if (count($n) == 1)
        return array_chunk($n[0], 1);

    // Add a NULL element to the beginning of the array
    array_unshift($uarr, NULL);

    // Use 'array_map' to transpose the 2D array
    $transpose = call_user_func_array('array_map', $uarr);

    // Use 'array_map' to filter out NULL values from each column
    return array_map('array_filter', $transpose);
}

// Define a function named 'bead_sort' that performs bead sort on an array
function bead_sort($uarr)
{
    // Create an array of poles based on the values in the input array
    foreach ($uarr as $e)
        $poles [] = array_fill(0, $e, 1);

    // Use 'array_map' to count the beads in each column of the transposed array
    return array_map('count', columns(columns($poles)));
}

// Output a message indicating the original array
echo 'Original Array : ' . '';

// Display the original array
print_r(array(5, 3, 1, 3, 8, 7, 4, 1, 1, 3));

// Output a newline character for better formatting
echo '
'.'After Bead sort : ' . '';

// Display the array after applying bead sort
print_r(bead_sort(array(5, 3, 1, 3, 8, 7, 4, 1, 1, 3)));
?>

Output:

Original Array :                                            
Array                                                       
(                                                           
    [0] => 5                                                
    [1] => 3                                                
    [2] => 1                                                
    [3] => 3                                                
    [4] => 8                                                
    [5] => 7                                                
    [6] => 4                                                
    [7] => 1                                                
    [8] => 1                                                
    [9] => 3                                                
)                                                           
                                                            
After Bead sort :                                           
Array                                                       
(                                                            
    [0] => 8                                                
    [1] => 7                                                
    [2] => 5                                                
    [3] => 4                                                
    [4] => 3                                                
    [5] => 3                                                
    [6] => 3                                                
    [7] => 1                                                
    [8] => 1                                                
    [9] => 1                                                
) 

Flowchart:

PHP Code Editor:

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