这种排序算法可以被认为是冒泡排序的一种变体吗？

Question

can this approach be considered a variation of bubble sort? if not then what are the key differences and what is the efficiency comparison between this approach and bubble sort?

def bubble_sort(arr):

    for i in range(len(arr)):
        for j in range(len(arr)-i):
            if arr[i] > arr[j+i]:
                arr[i], arr[j+i] = arr[j+i], arr[i]
    return arr


if __name__ == '__main__':
    arr = [21,4,1,3,9,20,25,6,21,14]
    print(bubble_sort(arr))

output : [1, 3, 4, 6, 9, 14, 20, 21, 21, 25]

Answer 1

Your code has implemented the algorithm selection sort rather than bubble sort . Though they are somewhat similar: they are both based on element swapping.

For selection sort, the algorithm's key though is to find the minimal or maximum element and swap at last:

The algorithm proceeds by finding the smallest (or largest, depending on sorting order) element in the unsorted sublist, exchanging (swapping) it with the leftmost unsorted element (putting it in sorted order), and moving the sublist boundaries one element to the right.

And your code can be improved to avoid unnecessary swaping:

import random

def my_sort(arr):

    for i in range(len(arr)):
        min_idx = i
        for j in range(len(arr)-i):
            if arr[min_idx] > arr[j+i]:
                min_idx = j + i
        arr[i],arr[min_idx] = arr[min_idx], arr[i]
    return arr


if __name__ == '__main__':
    for i in range(360):
        i = i + 1
        r = random.choices(range(i * 10), k=i)   # Get list of numbers
        r1 = r.copy()
        assert my_sort(r) == sorted(r1)