**Sorting Algorithm Tutorials - Herong's Tutorial Examples** - v6.10, by Dr. Herong Yang

Bubble Sort - Implementation in Perl

This section provides a tutorial on how to implement the Bubble Sort algorithm in Perl.

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 Perl implementation of Bubble Sort algorithm:

#- Sort_Function.pl #- Copyright (c) HerongYang.com. All Rights Reserved. #- sub bubbleSort { my ($a, $fromIndex, $toIndex) = @_; for ($i=$toIndex-1; $i>$fromIndex; $i--) { $isSorted = 1; for ($j=$fromIndex; $j<$i; $j++) { if (($a->[$j])>$a->[$j+1]) { $isSorted = 0; $d = $a->[$j+1]; $a->[$j+1] = $a->[$j]; $a->[$j] = $d; } } last if ($isSorted); } } # Functions for other sorting algorithms ... #- End 1;

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:

- Elements to be sorted are stored from "fromIndex" to "toIndex-1" inclusive.
- At the beginning of each iteration of loop "i", elements from "i+1" to "toIndex-1" are sorted.
- At the beginning of each iteration of loop "i", elements from "fromIndex" to "j+1" are not sorted.
- At the end of each iteration of loop "i", element at "i" will be the element with the highest order in the un-sorted section.
- The "break" statement is there just in case when the un-sorted section happen to be already sorted.

Here are the performance test results of bubbleSort() function using Perl 5.18. The execution of bubbleSort() is so slow. I have to reduce the number of tests to 10 and 1 to avoid long waiting time.

Array size: 10000 Average sorting time: 19343.8862792969 milliseconds Number of tests: 10 Performance: 1934.38862792969 O(N) microseconds Performance: 145.577250069532 O(N*Log2(N)) microseconds Performance: 0.193438862792969 O(N*N) microseconds Array size: 20000 Average sorting time: 78359.980859375 milliseconds Number of tests: 10 Performance: 3917.99904296875 O(N) microseconds Performance: 274.221578576619 O(N*Log2(N)) microseconds Performance: 0.195899952148438 O(N*N) microseconds Array size: 30000 Average sorting time: 177352.602050781 milliseconds Number of tests: 1 Performance: 5911.75340169271 O(N) microseconds Performance: 397.490932147987 O(N*Log2(N)) microseconds Performance: 0.19705844672309 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 Perl sort() 11 22 36 171 Insertion Sort 4125 16015 37098 Selection Sort 8054 31249 68985 Bubble Sort 19344 78360 177353

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

►Sorting Algorithms Implementations in Perl

Sort_Test.pl - Sorting Performance Test

Insertion Sort - Implementation in Perl

Selection Sort - Implementation in Perl

►Bubble Sort - Implementation in Perl

Quicksort - Implementation in Perl

Merge Sort - Implementation in Perl

Heap Sort - Implementation in Perl

Shell Sort - Implementation in Perl

Sorting Algorithms Implementations in Python