Sorting Algorithm Tutorials - Herong's Tutorial Examples - 6.12, by Herong Yang
Selection Sort - Performance
This section provides a tutorial on how to measure the performance of the Selection Sort algorithm. My first Java implementation of Selection Sort is performing at the O(N*N) order level.
Now let's see how my Java implementation of the Selection Sort algorithm performs. Here are the results with my SortTest.java class and HyArrays.selectionSort() function using JDK 13.
Array size: 10000 Average sorting time: 55 milliseconds Number of tests: 1000 Performance: 5.5 O(N) microseconds Performance: 0.4139162440379741 O(N*Log2(N)) microseconds Performance: 5.5E-4 O(N*N) microseconds Array size: 20000 Average sorting time: 250 milliseconds Number of tests: 1000 Performance: 12.5 O(N) microseconds Performance: 0.8748776338675273 O(N*Log2(N)) microseconds Performance: 6.25E-4 O(N*N) microseconds Array size: 30000 Average sorting time: 600 milliseconds Number of tests: 1000 Performance: 20.0 O(N) microseconds Performance: 1.3447480134545982 O(N*Log2(N)) microseconds Performance: 6.666666666666666E-4 O(N*N) microseconds
The results showed us that the performance of selection method is O(N*N), because the last performance line gave me a constant, when I increased the array size.
Comparing with the Insertion Sort implementation, the Selection Sort implementation is much slower.
As a reference, results from an older computer are listed below:
Array size: 1000 Average sorting time: 38 milliseconds Number of tests: 1000 Performance: 38.0 O(N) microseconds Performance: 3.813046611743762 O(N*Log2(N)) microseconds Performance: 0.038 O(N*N) microseconds Array size: 2000 Average sorting time: 153 milliseconds Number of tests: 1000 Performance: 76.5 O(N) microseconds Performance: 6.976245201813886 O(N*Log2(N)) microseconds Performance: 0.03825 O(N*N) microseconds Array size: 3000 Average sorting time: 347 milliseconds Number of tests: 1000 Performance: 115.66666666666667 O(N) microseconds Performance: 10.01378255586346 O(N*Log2(N)) microseconds Performance: 0.03855555555555556 O(N*N) microseconds
Table of Contents
Introduction of Sorting Algorithms
Java API for Sorting Algorithms
Insertion Sort Algorithm and Java Implementation
►Selection Sort Algorithm and Java Implementation
Selection Sort - Algorithm Introduction
Selection Sort - Java Implementation
Selection Sort - Implementation Improvements
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
Sorting Algorithms Implementations in Python