02. Selection Sort

Algorithm Pseudocode

  1. Start at beginning of the array, where index i = 0.
  2. Move through i to N where N is the length of the array.
  3. Select the min
  4. Swap the min with i.
  5. Increment i and loop.


This visualization makes it seem like selection sorting is fast, but in reality, this algorithm iterates through all elements (gray bars) to select the smallest value.


Selection sort is not stable.

Having a runtime of always quadratic, selection sort may present itself as not the best sorting algorithm. However, this algorithm could be useful if the cost of swapping items is high.


O(n2) comparisons, O(n) swaps

Implementation in Java

Here's a sample implementation written in Java. Note that it extends the Sort.java class.

import java.util.Arrays;
public class SelectionSort extends Sort {
  public static void main(String[] args) {
    int[] testInt = {1,6,2,3,6,7,4,2,5};
  public static void selectionSort(int[] input) {
    for (int i = 0; i < input.length; i++) {
      int minIndex = i;
      int min = input[i];
      // Iterate through array to find minimal value
      for (int j = i; j < input.length; j++) {
        if (input[j] < min) {
          // Replace with new min if new min found
          minIndex = j;
          min = input[j];
      // Swap with index at start of search
      swap(input, minIndex, i);

Ace your Technical Interview

Programming Interviews: Exposed

Ace your Technical Interview Try Algorithms

In today's tight job market, competition for programming jobs is hotter than ever. This third edition of a popular guide to programming interviews includes new code examples, information on the latest languages, new chapters on sorting and design patterns, tips on using LinkedIn, and a downloadable app to help prepare applicants for the interview.

$ Check price
29.9929.99Amazon 4.5 logo(94+ reviews)

More Algorithms resources

Learn how data is stored

Data Structures and Algorithms in Java

Learn how data is stored Try Data Structures

Algorithms are the procedures that software programs use to manipulate data structures. Besides clear and simple example programs, the author includes a workshop as a small demonstration program executable on a Web browser. The programs demonstrate in graphical form what data structures look like and how they operate.

$ Check price
64.9964.99Amazon 4.5 logo(97+ reviews)

More Data Structures resources