What is the Difference Between Bubble Sort and Insertion Sort?

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Bubble sort and insertion sort are both comparison-based sorting algorithms, but they differ in their methods and efficiency. Here are the main differences between the two:

  1. Method: Bubble sort compares adjacent elements and swaps them if they are not in order. In contrast, insertion sort constructs the final sorted list by moving one element at a time, comparing the current element to the previously sorted elements, and inserting it into the correct position.
  2. Swaps: Bubble sort includes more swaps, making it slower compared to insertion sort, which has fewer swaps and is faster.
  3. Stability: Both algorithms are stable sorting algorithms, meaning they preserve the relative order of equal elements in the sorted array.
  4. Time Complexity: Both bubble sort and insertion sort have a time complexity of O(n^2) in the worst and average cases, and O(n) in the best case (when the input array is already sorted).
  5. Space Complexity: Both algorithms have a space complexity of O(1), meaning they require a constant amount of additional memory for sorting.

In summary, insertion sort is generally considered more efficient and faster than bubble sort due to its fewer swaps and better performance, especially for smaller datasets.

Comparative Table: Bubble Sort vs Insertion Sort

Here is a table comparing the differences between Bubble Sort and Insertion Sort:

Feature Bubble Sort Insertion Sort
Swaps More Less
Story Maximums bubble out Lowest elements sink down
Direction Top to bottom (maximums move up) Bottom to top (lowest elements move down)
Time Complexity O(n^2) O(n^2)
Space Complexity O(1) O(1)
Stability Stable Stable

Both Bubble Sort and Insertion Sort are comparison-based sorting algorithms with a time complexity of O(n^2) and a space complexity of O(1). They are stable, meaning they preserve the relative order of elements with the same value. However, the main difference between the algorithms lies in their method:

  • In Bubble Sort, adjacent elements are compared and swapped if they are not in the correct order. This process is repeated until the entire list is sorted, with maximums bubbling up to the top.

  • In Insertion Sort, one element at a time is inserted into its correct position within the sorted portion of the list, moving from the bottom up. This process continues until the entire list is sorted.

While both algorithms have the same time and space complexity, Insertion Sort is generally considered faster and more efficient than Bubble Sort.