Use Python to learn the principles and practical application scenarios of selection sorting algorithm

Learn the basic ideas and applications of selection sorting through Python

Selection Sort is a simple and intuitive sorting algorithm. Its basic idea is to Select the smallest (or largest) element from the sorted data and place it at the end of the sorted area, then select the smallest (or largest) element from the remaining unsorted data and place it at the end of the sorted area, and so on, until All data is sorted.

The specific steps of selection sorting are as follows:

1. First, find the smallest (or largest) element from the data to be sorted, and exchange it with the first element.
2. Then, find the smallest (or largest) element from the remaining unsorted data and swap its position with the second element.
3. Repeat the above steps, sequentially exchanging the minimum (or maximum) value in the remaining unsorted data with the end element of the sorted area until all data is sorted.

The following is a code example using Python to implement selection sorting:

def selection_sort(arr):
    n = len(arr)
    for i in range(n-1):
        min_idx = i
        for j in range(i+1, n):
            if arr[j] < arr[min_idx]:
                min_idx = j
        arr[i], arr[min_idx] = arr[min_idx], arr[i] 

# 测试代码
arr = [64, 25, 12, 22, 11]
selection_sort(arr)
print("排序后的数组：")
for i in range(len(arr)):
    print(arr[i], end=" ")

The selection_sort function in the above code implements the selection sorting algorithm. In each loop, min_idx records the index of the minimum value in the current unsorted area, finds the minimum value in the unsorted area in the inner loop, and uses an exchange operation to combine it with the index of the sorted area. The last elements are swapped. Finally, through multiple loops, the entire array is sorted.

The output result of the above code is:

排序后的数组：
11 12 22 25 64

The time complexity of selection sorting is O(n^2), so it is not suitable for situations with large amounts of data. However, the implementation of selection sort is relatively simple and the code is easy to understand, so it still has certain application value in some specific scenarios.

Through the above code examples and explanations, we have learned the basic ideas and applications of selection sorting. I hope it will be helpful for you to understand and master the selection sort algorithm.

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