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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
function columns($uarr)
{
$n=$uarr;
if (count($n) == 0)
 return array();
else if (count($n) == 1)
 return array_chunk($n[0], 1);
array_unshift($uarr, NULL);
 $transpose = call_user_func_array('array_map', $uarr);
return array_map('array_filter', $transpose);
}
function bead_sort($uarr)
{
foreach ($uarr as $e)
 $poles []= array_fill(0, $e, 1);
return array_map('count', columns(columns($poles)));
}
echo 'Original Array : '.'
';
print_r(array(5,3,1,3,8,7,4,1,1,3));
echo '
'.'After Bead sort : '.'
';
print_r(bead_sort(array(5,3,1,3,8,7,4,1,1,3)));
?>

Sample 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:

Flowchart: Sort an array of positive integers using the Bead-Sort Algorithm

PHP Code Editor:

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC