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PHP Searching and Sorting Algorithm: Insertion sort

PHP Searching and Sorting Algorithm: Exercise-3 with Solution

Write a PHP program to sort a list of elements using Insertion sort.

Insertion sort is a simple sorting algorithm that builds the final sorted array (or list) one item at a time. It is much less efficient on large lists than more advanced algorithms such as quicksort, heapsort, or merge sort.

Pictorial Presentation : Insertion Sort

JavaScript Insertion sort

A graphical example of insertion sort :

Insertion sort animation

Animation Credits : Swfung8

Sample Solution :

PHP Code :

<?php

 function insertion_Sort($my_array)
{
	for($i=0;$i<count($my_array);$i++){
		$val = $my_array[$i];
		$j = $i-1;
		while($j>=0 && $my_array[$j] > $val){
			$my_array[$j+1] = $my_array[$j];
			$j--;
		}
		$my_array[$j+1] = $val;
	}
return $my_array;
}
$test_array = array(3, 0, 2, 5, -1, 4, 1);
echo "Original Array :\n";
echo implode(', ',$test_array );
echo "\nSorted Array :\n";
print_r(insertion_Sort($test_array));
?>

Sample Output:

Original Array :                                                    
3, 0, 2, 5, -1, 4, 1                                                
Sorted Array :                                                      
Array                                                               
(                                                                   
    [0] => -1                                                       
    [1] => 0                                                        
    [2] => 1                                                        
    [3] => 2                                                        
    [4] => 3                                                        
    [5] => 4                                                        
    [6] => 5                                                        
) 

Flowchart :

Flowchart: PHP - program of Insertion sort

PHP Code Editor:


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Previous: Write a PHP program to sort a list of elements using Heap sort.
Next: Write a PHP program to sort a list of elements using Selection sort.

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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