3. 插入排序

代码实现:

public class InsertSort {
    public static void main(String[] args) {
        InsertSort sort = new InsertSort();
        int[] arr = {8,4,6,1,2};
        System.out.println(Arrays.toString(sort.insertSort(arr)));
    }
    public int[] insertSort(int[] arr){
        int temp = arr[0];
        for (int i = 0; i < arr.length; i++) {
            for (int j = i; j > 0 ; j--) {
                if (arr[j] < arr[j -1]){
                    temp = arr[j -1];
                    arr[j -1] = arr[j];
                    arr[j] = temp;
                }
            }
        }
        return arr;
    }
}