[JAVA-자바] 1916번: 최소비용 구하기

 

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.PriorityQueue;
import java.util.StringTokenizer;

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

    static class Node implements Comparable<Node> {
        int next;
        int cost;

        Node(int next, int cost) {
            this.next = next;
            this.cost = cost;
        }

        @Override
        public int compareTo(Node o) {
            return this.cost - o.cost;
        }
    }

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

        int N = Integer.parseInt(br.readLine());
        int M = Integer.parseInt(br.readLine());

        List<List<Node>> graph = new ArrayList<>();
        for (int i = 0; i <= N; i++) {
            graph.add(new ArrayList<>());
        }

        for (int i = 0; i < M; i++) {
            StringTokenizer st = new StringTokenizer(br.readLine());
            int start = Integer.parseInt(st.nextToken());
            int next = Integer.parseInt(st.nextToken());
            int cost = Integer.parseInt(st.nextToken());
            graph.get(start).add(new Node(next, cost));
        }

        StringTokenizer st = new StringTokenizer(br.readLine());
        int startNode = Integer.parseInt(st.nextToken());
        int endNode = Integer.parseInt(st.nextToken());

        br.close();

        boolean[] visited = new boolean[N + 1];
        int[] cost = new int[N + 1];
        Arrays.fill(cost, Integer.MAX_VALUE);
        cost[startNode] = 0;

        PriorityQueue<Node> queue = new PriorityQueue<>();
        queue.add(new Node(startNode, cost[startNode]));

        while (!queue.isEmpty()) {
            Node cur = queue.poll();
            int currentNode = cur.next;

            if (visited[currentNode]) {
                continue;
            }
            visited[currentNode] = true;

            for (Node nextNode : graph.get(currentNode)) {
                if (cost[nextNode.next] > cost[currentNode] + nextNode.cost) {
                    cost[nextNode.next] = cost[currentNode] + nextNode.cost; // update
                    queue.add(new Node(nextNode.next, cost[nextNode.next]));
                }
            }
        }

        bw.write(cost[endNode] + "\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.