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
A graphical example of insertion sort :
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($test_array));
?>
Sample Output:
Original Array : 3, 0, 2, 5, -1, 4, 1 Sorted Array : Array ( [0] => -1 [1] => 0 [2] => 1 [3] => 2 [4] => 3 [5] => 4 [6] => 5 )
Flowchart :
PHP Code Editor:
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Previous: Write a PHP program to sort a list of elements using Heap sort.
Next: Write a PHP program to sort a list of elements using Selection sort.
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PHP: Tips of the Day
How to Sort Multi-dimensional Array by Value?
Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:
Example:
function sortByOrder($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
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