03. Bubble Sort

Algorithm Pseudocode

  1. Start at the outer loop, i = 0.
  2. Within the inner loop, compare each two consecutive values.
  3. If the value of the right cell has a key index lower than that of the left cell, swap.
  4. Repeat inner/outer loops until smaller values bubble to the top.
  5. *If no swaps occur in one entire inner loop, list is already sorted and you're done.


Here's a good visualization as to what's exactly happening.


Time: O(n2) but O(n) when nearly sorted.

Space: O(1)


Bubble sort is a stable sorting algorithm.

Bubble sort has a high overhead. In the case where the given input is reversed, the algorithm will take O(n2) time.

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 BubbleSort extends Sort {
  public static void main(String[] args) {
    int[] testInt = {1,6,2,3,6,7,4,2,5};
  public static void bubbleSort(int[] testInt) {
     * If flag keeps false, then no swaps occurred, meaning
     * our list is already sorted
    boolean flag;
    do {
      flag = false;
      for (int j = 0; j < testInt.length-1; j++) {
        if (testInt[j+1] < testInt[j]) {
          swap(testInt, j, j+1);
          flag = true;
    } while (flag);

Aching back from coding all day?

Prism Glasses

Aching back from coding all day? Try Back Problems

Ever feel achy from sitting crunched up on your computer table? Try lying down with these optical glasses that allow you to work on your laptop while lying flat on your back. This is the perfect solution with those with limited mobility or those who wish to prevent neck cramps and back strains.

$ Check price
4.454.45Amazon 4 logo(128+ reviews)

More Back Problems resources

Ace your Technical Interview

Elements of Programming Interviews

Ace your Technical Interview Try Algorithms

Learn all the different scenarios of . This book is jam packed with code snippets written in C++ and Java to give you the edge you need to ace your technical interviews. Problems come with detailed solutions as well as a hint in case you get stuck, and organized by difficulty level with several variants to help you apply your knowledge more widely.

$ Check price
39.9539.95Amazon 4 logo(240+ reviews)

More Algorithms resources