题解 | #数据分类处理#

import java.util.HashMap;
import java.util.HashSet;
import java.util.Scanner;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.Map;

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

        while(in.hasNext()){
            solution1(in);
            // solution2(in);
        }
    }


    /**
     * TreeSet + StringBuilder
     * @param in
     */
    private static void solution1(Scanner in){
        int INum = in.nextInt();
        long[] ISeq = new long[INum];

        for(int i=0; i<INum; i++){
            ISeq[i] = in.nextLong();
        }

        int RNum = in.nextInt();
        // 过滤重复且排序
        TreeSet<Long> RSet = new TreeSet<>();

        for(int i=0; i<RNum; i++){
            RSet.add(in.nextLong());
        }

        int total = 0;
        StringBuilder result = new StringBuilder();
        for(Long Ri: RSet){
            int count = 0;
            StringBuilder sb = new StringBuilder();
            for(int k=0; k<INum; k++){
                if(String.valueOf(ISeq[k]).contains(String.valueOf(Ri))){
                    count++;
                    sb.append(k+" "+ISeq[k]+" ");
                }
            }
            if(count > 0){
                result.append(Ri+" "+count+" ");
                result.append(sb);
                total += 2+count*2;
            }
        }

        result.insert(0, total+" ");

        System.out.println(result);
    }


    /**
     * HashSet + TreeMap + HashMap
     * @param in
     */
    private static void solution2(Scanner in){
        int INum = in.nextInt();
        long[] ISeq = new long[INum];

        for(int i=0; i<INum; i++){
            ISeq[i] = in.nextLong();
        }

        int RNum = in.nextInt();
        // 过滤重复
        HashSet<Long> RSet = new HashSet<>();

        for(int i=0; i<RNum; i++){
            RSet.add(in.nextLong());
        }

        // Ri -> 个数
        TreeMap<Long, Integer> RCountMap = new TreeMap<>();
        // Ri -> 位置及值
        HashMap<Long, String> RIndexValueMap = new HashMap<>();
        for(Long Ri: RSet){
            for(int k=0; k<INum; k++){
                if(String.valueOf(ISeq[k]).contains(String.valueOf(Ri))){
                    RCountMap.put(Ri, RCountMap.getOrDefault(Ri, 0)+1);
                    if(RIndexValueMap.get(Ri) != null){
                        RIndexValueMap.put(Ri, RIndexValueMap.get(Ri)+k+" "+ISeq[k]+" ");
                    }else{
                        RIndexValueMap.put(Ri, k+" "+ISeq[k]+" ");
                    }
                }
            }
        }

        int total = RCountMap.size() * 2;
        for(int count: RCountMap.values()){
            total += count * 2;
        }

        StringBuilder result = new StringBuilder(total+" ");
        for(Map.Entry<Long, Integer> entry: RCountMap.entrySet()){
            result.append(entry.getKey()+" "+entry.getValue()+" ");
            result.append(RIndexValueMap.get(entry.getKey()));
        }

        System.out.println(result);
    }
}