题解 | #数据分类处理#

import java.util.*;
import java.util.stream.Collectors;

// 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 I =in.nextLine();
        String R =in.nextLine();
      
        List<String> rStrListz = Arrays.asList(R.split(" "));
        List<String> rStrList = new ArrayList<>();
        rStrList.addAll(rStrListz);
        List<Integer> rList =rStrList.stream().map(item->Integer.parseInt(item)).collect(Collectors.toList());
        Integer rFirst  = rList.get(0);
        rList.remove(0);


        List<String> IStrListz = Arrays.asList(I.split(" "));
        List<String> IStrList = new ArrayList<>();
        IStrList.addAll(IStrListz);
       
        String iFirst  = IStrList.get(0);
        IStrList.remove(0);

        List<Integer> duan = new ArrayList<>();
          List<Integer> duanSize = new ArrayList<>();
        List<List<Integer>> duanList = new ArrayList<>();
        int max = 0;
        
        rList = new ArrayList<>(new HashSet<>(rList));
        Collections.sort(rList);
        for(int i=0;i<rList.size();i++){
            List<Integer> duanItem = new ArrayList<>();
          
            for(int j=0;j<IStrList.size();j++){
                if(IStrList.get(j).contains(rList.get(i).toString())){
                      duanItem.add(j);
                      duanItem.add(Integer.parseInt(IStrList.get(j)));
                }
            }
            if(duanItem.size()!=0){
                duan.add(rList.get(i));
                max+=1;
                duanSize.add(duanItem.size()/2);
                max+=1;
                duanList.add(duanItem);
                max+=duanItem.size();
            }
        }
        System.out.print(max+" ");
        for(int i=0;i<duan.size();i++){
            System.out.print(duan.get(i)+" ");
            System.out.print(duanSize.get(i)+" ");
            
            duanList.get(i).forEach(item->{
                System.out.print(item+" ");
            });

        }




    }
}