/**
 * @Auther: Arsenal
 * @Date: 2020-03-17 0:37
 * @Description: 选择排序
 */
public class SelectionSort {
    public static void main(String[] args) {
        //int[] arr = {3, 9, -1, 10, -2};
        //System.out.println("原始的数组:" + Arrays.toString(arr));

        int[] arr = new int[80000];
        for (int i = 0; i < 80000; i++) {
            arr[i] = (int) (Math.random() * 80000);
        }
        long start = System.currentTimeMillis();
        selectionSort(arr); //2305毫秒
        long end = System.currentTimeMillis();
        System.out.println("80000个数字排序所用时间:" + (end - start));
    }

    /**
     * 选择排序
     * @param arr 数组
     */
    public static void selectionSort(int[] arr) {

        for (int i = 0; i < arr.length - 1; i++) {
            int min = arr[i];
            int minIndex = i;

            for (int j = i + 1; j < arr.length; j++) {
                if (min > arr[j]) {
                    min = arr[j];
                    minIndex = j;
                }
            }
            //优化
            if (minIndex != i) { //交换
                arr[minIndex] = arr[i];
                arr[i] = min;
            }
            //System.out.println("第" + (i + 1) + "趟排序后的数组:");
            //System.out.println(Arrays.toString(arr));
        }
    }

}