题解 | 小红书推荐系统

import java.util.*;
import java.io.*;

// 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) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        br.close();
        Map<String, Integer> freqMap = new HashMap<>(st.countTokens());
        while (st.hasMoreTokens()) {
            String keywords = st.nextToken();
            freqMap.put(keywords, freqMap.getOrDefault(keywords, 0) + 1);
        }
        List<Map.Entry<String, Integer>> keywordsList = new ArrayList<>();
        for (Map.Entry<String, Integer> freqEntry : freqMap.entrySet()) {
            if (freqEntry.getValue() >= 3) {
                keywordsList.add(freqEntry);
            }
        }
        keywordsList.sort((e1, e2)->{
            int c = Integer.compare(e2.getValue(), e1.getValue());
            return c != 0 ? c : e1.getKey().compareTo(e2.getKey());
        });
        StringBuilder sb = new StringBuilder();
        for (Map.Entry<String, Integer> keywordsEntry : keywordsList) {
            sb.append(keywordsEntry.getKey()).append(System.lineSeparator());
        }
        System.out.println(sb.toString());
    }
}