题解 | #手串#

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Scanner;

public class Main {
    private static int num;
    private static int series;
    private static final int times = 2;
    private static HashMap<Integer, List<Integer>> colourLocMap = new HashMap<>();

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

        while(in.hasNext()){
            solution(in);
        }
    }

    /**
     * 模拟法
     * @param in
     */
    private static void solution(Scanner in){
        num = in.nextInt();
        series = in.nextInt();
        int colours = in.nextInt();

        int kinds;
        for(int i=1; i<=num; i++){
            kinds = in.nextInt();
            int colour;
            List<Integer> list;
            for(int j=1; j<=kinds; j++){
                colour = in.nextInt();
                list = colourLocMap.get(colour);
                if(list != null){
                    list.add(i);
                    colourLocMap.put(colour, list);
                }else{
                    colourLocMap.put(colour, new ArrayList<>(Collections.singletonList(i)));
                }
            }
        }

        int result = 0;
        for(int i=1; i<=colours; i++){
            if(!isColourOk(i)){
                result++;
            }
        }

        System.out.println(result);
    }

    private static boolean isColourOk(int colour){
        // locations有序(从小到大)
        List<Integer> locations = colourLocMap.get(colour);

        // 任何珠子都没涂该颜色
        if(locations != null){
            int size = locations.size();
            if(size >= times){
                for(int i=1; i<size; i++){
                    if(locations.get((i-1)%size)+series-1 >= locations.get(i%size)){
                        return false;
                    }
                }

                if((locations.get(size-1)+series-1)%num >= locations.get(0)){
                    return false;
                }
            }
        }
        return true;
    }
}