[JAVA-자바] 1865번: 웜홀

 

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.Arrays;
import java.util.List;
import java.util.StringTokenizer;

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


    public static class Node {
        int start;
        int to;
        int cost;

        Node(int s, int t, int c) {
            this.start = s;
            this.to = t;
            this.cost = c;
        }
    }


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

        int TC = Integer.parseInt(br.readLine());

        for (int test = 0; test < TC; test++) {
            StringTokenizer st = new StringTokenizer(br.readLine());

            int N = Integer.parseInt(st.nextToken());
            int M = Integer.parseInt(st.nextToken());
            int W = Integer.parseInt(st.nextToken());

            List<Node> graph = new ArrayList<>();

            for (int i = 0; i < M; i++) {
                st = new StringTokenizer(br.readLine());

                int start = Integer.parseInt(st.nextToken());
                int to = Integer.parseInt(st.nextToken());
                int cost = Integer.parseInt(st.nextToken());

                graph.add(new Node(start, to, cost));
                graph.add(new Node(to, start, cost));
            }
            for (int i = 0; i < W; i++) {
                st = new StringTokenizer(br.readLine());

                int start = Integer.parseInt(st.nextToken());
                int to = Integer.parseInt(st.nextToken());
                int cost = Integer.parseInt(st.nextToken());

                graph.add(new Node(start, to, -cost));
            }
            boolean flag = bellmanFord(N, graph);
            bw.write(flag ? "YES\n" : "NO\n");
        }
        br.close();

        bw.close();
    }

    public static boolean bellmanFord(int N, List<Node> graph) {
        int[] dist = new int[N + 1];
        Arrays.fill(dist, Integer.MAX_VALUE);
        dist[0] = 0;

        for (int i = 1; i <= N; i++) {
            graph.add(new Node(0, i, 0)); // add
        }

        for (int i = 0; i < N; i++) {
            for (Node node : graph) {
                if (dist[node.start] != Integer.MAX_VALUE && dist[node.to] > dist[node.start] + node.cost) {
                    dist[node.to] = dist[node.start] + node.cost;
                }
            }
        }

        for (Node node : graph) {
            if (dist[node.start] != Integer.MAX_VALUE && dist[node.to] > dist[node.start] + node.cost) {
                return true;
            }
        }

        return false;
    }
}

 

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.