选择排序

选择排序
分析：升序为例，遍历数组，记录最大数索引，最后和上次最后索引的数交换。

public class Test08 {
    //选择排序
    public static void selectionSort(int[] arr) {
        for (int i = 1; i < arr.length; i++) {
            int index = 0;
            int lastIndex = arr.length - i;
            for (int j = 1; j <= lastIndex; j++) {
                if (arr[index] < arr[j]) {
                    index = j;
                }
            }
            if (index != lastIndex) {
                int temp = arr[lastIndex];
                arr[lastIndex] = arr[index];
                arr[index] = temp;
            }
        }
    }

    public static void main(String[] args) {
        int[] arr = {20, 1, 82, 23, 13, 15, 0};
        printArray(arr, "排序前：");
        selectionSort(arr);
        printArray(arr, "排序后：");
    }

    public static void printArray(int[] arr, String message) {
        System.out.print(message);
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }
}