Bubble Sort

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November 1, 2022

Coding & Algorithm Interview  Data Structures & Algorithms 


In the world of computer programming, sorting algorithms play a crucial role in organizing and arranging data in a specific order. One popular but simple algorithm is the Bubble Sort, which is often used to sort small datasets or as an educational tool for beginners to understand the basic principles of sorting algorithms. In this tech blog, we will take a closer look at Bubble Sort, how it works, its advantages and disadvantages, and its implementation in code.

How Does Bubble Sort Work?

Bubble Sort is a comparison-based sorting algorithm that works by repeatedly swapping adjacent elements if they are in the wrong order until the entire dataset is sorted. The algorithm gets its name from the way smaller elements “bubble up” to the top of the list as the algorithm iterates through the data. The basic idea behind Bubble Sort is to compare adjacent elements in the dataset and swap them if they are in the wrong order. This process is repeated multiple times until the entire dataset is sorted.

Here’s a step-by-step breakdown of how Bubble Sort works:

  1. Start with the first element in the dataset.
  2. Compare it with the adjacent element.
  3. If the adjacent element is smaller, swap them.
  4. Move to the next pair of adjacent elements and repeat the comparison and swapping process.
  5. Continue this process until the end of the dataset.
  6. After the first iteration, the largest element will have “bubbled up” to the last position.
  7. Repeat the process for the remaining unsorted portion of the dataset until the entire dataset is sorted.

Advantages of Bubble Sort

  1. Simplicity: Bubble Sort is a straightforward algorithm that is easy to understand and implement. It serves as a good introduction to sorting algorithms for beginners.
  2. Space Complexity: Bubble Sort has a space complexity of O(1), as it only requires a constant amount of additional space to store temporary variables for swapping elements.
  3. Suitable for Small Datasets: Bubble Sort can be efficient for small datasets where the overhead of more complex sorting algorithms may not be necessary.

Disadvantages of Bubble Sort

  1. Time Complexity: Bubble Sort has a time complexity of O(n^2) in the worst and average cases, making it inefficient for large datasets. It requires multiple passes through the entire dataset, which can be time-consuming.
  2. Inefficient: Bubble Sort often involves unnecessary comparisons and swaps, even when the dataset is already sorted or nearly sorted, which can further degrade its performance.
  3. Not Suitable for Large Datasets: Due to its time complexity, Bubble Sort is not recommended for sorting large datasets or real-time applications where efficiency is critical.

Implementation in Code

Here’s a simple implementation of Bubble Sort in Python:

def bubble_sort(arr):
    n = len(arr)
    for i in range(n):
        # Last i elements are already sorted
        for j in range(0, n-i-1):
            # Swap if the element found is greater
            # than the next element
            if arr[j] > arr[j+1]:
                arr[j], arr[j+1] = arr[j+1], arr[j]


Bubble Sort is a simple but inefficient sorting algorithm that can be used for small datasets or as a learning tool for beginners. While it has some advantages in terms of simplicity and space complexity, its time complexity and inefficiency make it unsuitable for large datasets or real-time applications. It’s important to understand the strengths and weaknesses of Bubble Sort and choose the appropriate sorting algorithm for different use cases.