题解 | 小红书推荐系统

朴实无华的排序，频率相同按字典序排序，否则按频率降序排序

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String line = in.nextLine();

        String[] arr = line.split(" ");
        Map<String, Integer> map = new HashMap<>();
        for (int i = 0; i < arr.length; i++) {
            map.put(arr[i], map.getOrDefault(arr[i], 0) + 1);
        }

        ArrayList<KeyWord> list = new ArrayList<>();
        map.forEach((k, v) -> {
            if(v >= 3) list.add(new KeyWord(k, v));
        });
        list.sort((o1, o2) -> {
            if(o1.freq == o2.freq) return o1.key.compareTo(o2.key);
            else return o2.freq - o1.freq;
        });
        list.forEach(e -> System.out.println(e.key));
    }
}

class KeyWord {
    String key;
    int freq;

    public KeyWord(String key, int freq) {
        this.key = key;
        this.freq = freq;
    }
}