Sorting Algorithm Tutorials - Herong's Tutorial Examples - 6.12, by Herong Yang
Bubble Sort - Implementation in PHP
This section provides a tutorial on how to implement the Bubble Sort algorithm in PHP.
Bubble Sort is a simple and slow sorting algorithm that repeatedly steps through the collection, compares each pair of adjacent elements and swaps them if they are in the wrong order.
The basic idea of Bubble Sort algorithm can be described as these steps:
1. Data elements are grouped into two sections: a sorted section and an un-sorted section.
2. Go through every element in the un-sorted section and re-arrange its position with its neighbor to put the element with higher order on the higher position. At the end, the element with the highest order will be on top of the un-sorted section, and moved to the bottom of the sorted section.
3. Repeat step 2 until no more elements left in the un-sorted section.
In the sorting algorithm, if you watch the move of the elements with higher orders, they are like bubbles in the water, floating slowly from the bottom to the top.
Here is my PHP implementation of Bubble Sort algorithm:
<?php #- Sort_Functions.php #- Copyright (c) 2015 HerongYang.com. All Rights Reserved. #- function bubbleSort(&$a, $fromIndex, $toIndex) { for ($i=$toIndex-1; $i>$fromIndex; $i--) { $isSorted = true; for ($j=$fromIndex; $j<$i; $j++) { if (($a[$j])>$a[$j+1]) { $isSorted = false; $d = $a[$j+1]; $a[$j+1] = $a[$j]; $a[$j] = $d; } } if ($isSorted) break; } } # Functions for other sorting algorithms ... ?>
The following diagram illustrates how this implementation works:
--17 42 53 67 ... 92 | | | | | +---+---+---------------+---+---+---+---+---+---------------+ | | | / 29 36 11 ... 24 39 | | | | fromIndex j i toIndex-1
Note that:
Here are the performance test results of bubbleSort() function using PHP 5.6.
Array size: 10000 Average sorting time: 6846.6 milliseconds Number of tests: 10 Performance: 684.66 O(N) microseconds Performance: 51.525799207825 O(N*Log2(N)) microseconds Performance: 0.068466 O(N*N) microseconds Array size: 20000 Average sorting time: 28426.6 milliseconds Number of tests: 5 Performance: 1421.33 O(N) microseconds Performance: 99.479186187595 O(N*Log2(N)) microseconds Performance: 0.0710665 O(N*N) microseconds Array size: 30000 Average sorting time: 66524 milliseconds Number of tests: 1 Performance: 2217.4666666667 O(N) microseconds Performance: 149.09669474509 O(N*Log2(N)) microseconds Performance: 0.073915555555556 O(N*N) microseconds
Here is the comparison of bubbleSort() performance with other sorting functions. As you can see, Bubble Sort is much slower than other sorting functions.
Array Size 10000 20000 30000 100000 200000 300000 ---------- ----- ----- ----- ------ ------ ------ JDK Arrays.sort 25 66 112 PHP sort() 3 7 13 75 Insertion Sort 2213 9484 23329 Selection Sort 3580 14129 33808 Bubble Sort 6847 28427 66524
Table of Contents
Introduction of Sorting Algorithms
Java API for Sorting Algorithms
Insertion Sort Algorithm and Java Implementation
Selection Sort Algorithm and Java Implementation
Bubble Sort Algorithm and Java Implementation
Quicksort Algorithm and Java Implementation
Merge Sort Algorithm and Java Implementation
Heap Sort Algorithm and Java Implementation
Shell Sort Algorithm and Java Implementation
►Sorting Algorithms Implementations in PHP
Sort_Test.php - Sorting Performance Test
Insertion Sort - Implementation in PHP
Selection Sort - Implementation in PHP
►Bubble Sort - Implementation in PHP
Quicksort - Implementation in PHP
Merge Sort - Implementation in PHP
Heap Sort - Implementation in PHP
Shell Sort - Implementation in PHP
Sorting Algorithms Implementations in Perl
Sorting Algorithms Implementations in Python