Demystifying the Bubble Sort Algorithm: A Beginner‘s Guide

Hello friend! Understanding the concepts behind basic sorting algorithms is incredibly valuable even as a seasoned programmer. It builds strong foundations to then understand more complex computer science ideas.

So let me walk you through bubble sort – likely the simplest sorting technique. We will explore aspects like:

  • How the bubble sort algorithm works 👨‍💻
  • Step-by-step sort animations ⏰
  • Implementing bubble sort in code 🖥️
  • Comparing complexity and efficiency 📊
  • Real-world applications 📱
  • Common questions answered 💡

Sound exciting? Let‘s get started!

What Exactly is Bubble Sort?

Bubble sort is a beginner friendly sorting algorithm that functions by comparing adjacent elements in a list and swapping them to sort in ascending/descending order.

Some key points about bubble sort to remember are:

  • It is called "bubble" sort because smaller elements slowly bubble up similar to bubbles in a glass of water
  • It sorts data by repeatedly stepping through lists comparing adjacent elements
  • Larger values get pushed to the end while smaller ones move to the start

Below you can observe bubble sort visually sorting a random list of numbers:

Bubble sort animation

Now that you have an idea what bubble sort looks like, let me walk you through precisely how it functions behind the scenes. 🧑‍💻

Step-By-Step Working of Bubble Sort Algorithm

The bubble sort algorithm starts by comparing two adjacent elements of a list. If elements are not already sorted in the desired order, then it swaps them.

It keeps traversing the list until no swaps occur at which point the list is fully sorted.

How it Works:

  1. Start loop from first element
  2. Compare current element to adjacent element on right
  3. If not in correct order, swap elements
  4. Move to next element and repeat step 2 & 3
  5. Largest values slowly ‘bubble‘ up to end of list
  6. Repeat until all data sorted

Allow me to demonstrate this visually:

Initial List State

Initial List for Bubble Sort

First Pass

  • 5 and 1 compared → 1 smaller so no swap
  • 1 and 4 compared → 1 smaller so no swap
  • 4 and 2 compared → 4 bigger so swap

Bubble Sort First Pass

Second Pass

  • 1 and 4 compared → 1 smaller so no swap
  • 4 and 2 compared → 2 smaller so swap
  • 2 and 5 compared → 2 smaller so no swap

Bubble Sort Second Pass

Final Pass

No more unsorted elements remaining!

I hope this gives you insight into how bubble sort peeks through the list while displacing incorrect elements. 😊

Python Implementation of Bubble Sort

Enough theory, let me show you a Python code sample to implement bubble sort:

def bubble_sort(arr):
    sorted = False

    while not sorted:
        sorted = True

        for num in range(len(arr) - 1):
            if arr[num] > arr[num + 1]:
                sorted = False
                arr[num], arr[num + 1] = arr[num + 1], arr[num] 

random_list = [5, 2, 9, 1]


[1, 2, 5, 9]  

The key aspects are:

  • sorted flag that denotes if a swap occurred
  • While unsorted, traverse adjacent elements
  • Swap elements using tuple assignment
  • Repeat passes till no swap needed

This implements the conceptual logic we discussed earlier in actual code!

Complexity and Efficiency Analysis

Now you might be wondering – how efficient is bubble sort? What is its time and space complexity?

Glad you asked! Let me summarize the key analysis of bubble sort complexity below:

Performance AspectComplexityNotes
Time Complexity
  • Best Case: O(n)
  • Average Case: O(n^2)
  • Worst Case: O(n^2)
Quadratic time complexity
Space ComplexityO(1)Sorts in-place
StabilityStableDoes not change equal element order


  • Bubble sort runtime ranges from linear O(n) for an optimally sorted list to O(n^2) on average/worst case
  • Space used is constant O(1) since sorting happens internally
  • Maintains element stability

Therefore, we conclude that bubble sort works best for smaller list sizes.

For larger data sets, advanced algorithms like quicksort and merge sort are used.

Real-World Applications of Bubble Sort

You may be wondering if bubble sort has any practical applications given its inefficiency for large data.

Well here are two examples where bubble sort shines:

1. Sorting Smaller Lists

Bubble sort performs best when list sizes are below 20-25 elements. Its simplicity is an advantage here over other complex algorithms.

2. Educational Implementations

The straightforward logic of bubble sort allows beginners to easily implement it from scratch. This makes it ideal for getting started with coding sorting algorithms.

So while outdated for modern systems, bubble sort still offers pedagogical value for new programmers!

How Does Bubble Sort Compare to Other Sorts?

I‘m sure you want to know how bubble sort performance compares to more advanced algorithms like quicksort and merge sort.

Here is a quick rundown:

Sorting AlgorithmTime ComplexitySpace ComplexityStability
Bubble SortBest: O(n)
Avg: O(n^2)
Worst: O(n^2)
Insertion SortBest: O(n)
Avg: O(n^2)
Worst: O(n^2)
Merge SortO(nlogn)O(n)Yes
QuicksortBest: O(nlogn)
Avg: O(nlogn)
Worst: O(n^2)


  • Bubble sort is equivalent to insertion sort in efficiency
  • It is outperformed by advanced algorithms like merge and quick sort
  • But bubble sort sorts data in-place unlike merge sort

Hope this gives you perspective on where bubble sort fits in 😀

Final Thoughts

And there you have it! We went from discussing what bubble sort is to step-by-step visualizations to Python code and complexity analysis.

Key takeaways:

💡 Bubble sort easy visualization makes it ideal for education
💡 It works by swapping adjacent elements to sort small lists
💡 The algorithm has a time complexity of O(n^2) limiting large scale use

I had a great time explaining the fundamentals of bubble sort to you! Let me know in comments if you have any other questions.
Keep learning!

Did you like those interesting facts?

Click on smiley face to rate it!

Average rating 0 / 5. Vote count: 0

No votes so far! Be the first to rate this post.

      Interesting Facts
      Login/Register access is temporary disabled