解法：简单语法题

package com.sky;

import java.util.*;

public class Test1 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int M = sc.nextInt();

        List<String> words = new ArrayList<>(N);

        for (int i = 0; i < N; i++) {
            String word = sc.next();
            words.add(word);
        }

        Comparator<String> customComparator = (s1, s2) -> {
            boolean s1Contains = s1.contains("PDD");
            boolean s2Contains = s2.contains("PDD");
            if (s1Contains && !s2Contains) {
                return -1;
            } else if (!s1Contains && s2Contains) {
                return 1;
            } else {
                return s1.compareTo(s2);
            }
        };

        Collections.sort(words, customComparator);

        for (int i = 0; i < M; i++) {
            System.out.println(words.get(i));
        }

    }
}