使用Arrays.sort默认的从小到大排序就行

import java.util.*;

public class Main{
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int k = sc.nextInt();
        int arr[] = new int[n];
        for(int i = 0;i < arr.length;i++){
            arr[i] = sc.nextInt();
        }
        Arrays.sort(arr);
        for(int j = 0;j<k;j++){
            System.out.print(arr[j] + " ");
        }
        System.out.println();
    }
    
    
}