[JAVA-자바] 1043번: 거짓말

 

소스코드:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.StringTokenizer;

public class Main {
    static BufferedReader br;
    static BufferedWriter bw;

    public static void main(String[] args) throws IOException {
        br = new BufferedReader(new InputStreamReader(System.in));
        bw = new BufferedWriter(new OutputStreamWriter(System.out));

        StringTokenizer st = new StringTokenizer(br.readLine());
        int N = Integer.parseInt(st.nextToken());
        int M = Integer.parseInt(st.nextToken());

        HashSet<Integer> whoKnow = new HashSet<>();
        Queue<Integer> queue = new LinkedList<>();

        st = new StringTokenizer(br.readLine());
        int count = Integer.parseInt(st.nextToken());
        for (int i = 0; i < count; i++) {
            int number = Integer.parseInt(st.nextToken());
            whoKnow.add(number);
            queue.add(number);
        }

        List<List<Integer>> partyList = new ArrayList<>();
        for (int i = 0; i < M; i++) {
            List<Integer> temp = new ArrayList<>();
            st = new StringTokenizer(br.readLine());
            int loop = Integer.parseInt(st.nextToken());
            for (int j = 0; j < loop; j++) {
                temp.add(Integer.parseInt(st.nextToken()));
            }
            partyList.add(temp);
        }
        br.close();

        boolean[] visitedParty = new boolean[M];

        while (!queue.isEmpty()) {
            int current = queue.poll();

            for (int i = 0; i < M; i++) {
                if (visitedParty[i]) {
                    continue;
                }

                List<Integer> party = partyList.get(i);
                if (party.contains(current)) {
                    visitedParty[i] = true;

                    for (int person : party) {
                        if (!whoKnow.contains(person)) {
                            whoKnow.add(person);
                            queue.add(person);
                        }
                    }
                }
            }
        }

        int result = 0;
        for (List<Integer> party : partyList) {
            boolean hasTruth = false;

            for (int person : party) {
                if (whoKnow.contains(person)) {
                    hasTruth = true;
                    break;
                }
            }

            if (!hasTruth) {
                result++;
            }
        }
        
        bw.write(result + "\n");
        bw.close();
    }
}

 

글의 내용 중 잘못된 점이나 수정이 필요한 부분, 혹은 궁금한 사항이 있다면 언제든 댓글로 남겨주시면 감사하겠습니다.

여러분의 피드백은 더 나은 글을 작성하는 데 큰 도움이 됩니다. 감사합니다.