Detailed explanation of the implementation method of Java selection sort algorithm

Java Selection Sort Code Detailed Explanation and Implementation Method

Selection Sort is a simple and intuitive sorting algorithm. Its basic idea is that each The pass selects the smallest (or largest) element from the data elements to be sorted and places it at the beginning of the sequence until all the data elements to be sorted are exhausted. The main advantages of the selection sorting method are that it is simple in idea, easy to implement, and does not require additional storage space, so it shows good performance on some simple sorting problems.

Below we explain in detail the implementation method of selection sorting method and give specific Java code examples.

Implementation method of selection sorting method:

1. Find the smallest (largest) element from the sequence to be sorted and place it at the starting position of the sequence.
2. Continue to find the smallest (largest) element from the remaining unsorted elements and place it at the end of the sorted sequence.
3. Repeat step 2 until all elements are sorted.

Java code example:

public class SelectionSort {
    public static void selectionSort(int[] arr) {
        int n = arr.length;
        for (int i = 0; i < n-1; i++) {
            int min_idx = i;
            for (int j = i+1; j < n; j++) {
                if (arr[j] < arr[min_idx]) {
                    min_idx = j;
                }
            }
            int temp = arr[min_idx];
            arr[min_idx] = arr[i];
            arr[i] = temp;
        }
    }

    public static void main(String[] args) {
        int[] arr = {64, 25, 12, 22, 11};
        selectionSort(arr);
        System.out.println("排序后的数组：");
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
    }
}

The running result is: 11 12 22 25 64

In the above code, we define a class named SelectionSort, where Contains a static method named selectionSort, which receives an integer array as a parameter and performs selection sorting on it. In the main method, we define an integer array arr and call the selectionSort method to sort it. Finally, we print out the sorted array through a loop.

The time complexity of the selection sort method is O(n^2), where n is the length of the sequence to be sorted. This makes the selection sort method less efficient for sorting large-scale data. However, in some small-scale or partially ordered data sorting problems, the selection sort method can still perform very well.

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