結果

問題 No.160 最短経路のうち辞書順最小
コンテスト
ユーザー jp_ste
提出日時 2016-06-06 21:32:23
言語 Java
(openjdk 23)
結果
WA  
実行時間 -
コード長 5,007 bytes
コンパイル時間 2,637 ms
コンパイル使用メモリ 79,604 KB
実行使用メモリ 52,460 KB
最終ジャッジ日時 2024-10-08 16:43:47
合計ジャッジ時間 5,578 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 4
other WA * 26
権限があれば一括ダウンロードができます

ソースコード

diff # 

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.NoSuchElementException;

public class Main {
    static FastScanner scan = new FastScanner();
    static PrintWriter out = new PrintWriter(System.out);
    
    static int n, m, s, g;
    
    public static void main(String[] args) {
        n = scan.nextInt();
        m = scan.nextInt();
        s = scan.nextInt();
        g = scan.nextInt();
        
        Node[] nodes = new Node[n];
        long[] dp = new long[n];
        int[] path = new int[n];
        
        for(int i=0; i<n; i++) {
            nodes[i] = new Node(i);
            dp[i] = -1;
            path[i] = -1;
        }
        
        for(int i=0; i<m; i++) {
            int a = scan.nextInt();
            int b = scan.nextInt();
            int c = scan.nextInt();
            nodes[a].edges.add(new Edge(b, c));
            nodes[b].edges.add(new Edge(a, c));
        }
        
        dijkstra(nodes, dp, path, s);
        
        StringBuilder sb = new StringBuilder();
        sb.append(g);
        int next = path[g];
        while(next != -1) {
            sb.append(" ");
            sb.append(next);
            next = path[next];
        }
        System.out.println(sb.reverse().toString());
    }

    static void dijkstra(Node[] nodes, long[] dp, int[] path, int s) {

        Arrays.fill(dp, -1);
        dp[s] = 0;

        LinkedList<Node> q = new LinkedList<>();
        q.add(nodes[s]);

        while (!q.isEmpty()) {

            Node now = q.poll();

            for (int i = 0; i < now.edges.size(); i++) {
                int toId = now.edges.get(i).toId;
                long toCost = now.edges.get(i).toCost;

                long nextCost = dp[now.id] + toCost;
                if (dp[toId] < 0 || nextCost <= dp[toId]) {
                    
                    if(nextCost == dp[toId]) {
                        if(path[toId] > now.id) {
                            path[toId] = now.id;
                        }
                    } else {
                        dp[toId] = nextCost;
                        path[toId] = now.id;
                        q.add(nodes[toId]);
                    }
                }
            }
        }
    }

    static class Node {
        int id;
        ArrayList<Edge> edges = new ArrayList<>();

        Node(int id) {
            this.id = id;
        }
    }

    static class Edge {
        int toId;
        long toCost;

        Edge(int id, long cost) {
            toId = id;
            toCost = cost;
        }
    }
    
    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;

        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            } else {
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }

        private int readByte() {
            if (hasNextByte())
                return buffer[ptr++];
            else
                return -1;
        }

        private static boolean isPrintableChar(int c) {
            return 33 <= c && c <= 126;
        }

        private void skipUnprintable() {
            while (hasNextByte() && !isPrintableChar(buffer[ptr]))
                ptr++;
        }

        public boolean hasNext() {
            skipUnprintable();
            return hasNextByte();
        }

        public String next() {
            if (!hasNext())
                throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while (isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public int nextInt() {
            if (!hasNext())
                throw new NoSuchElementException();
            int n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while (true) {
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                } else if (b == -1 || !isPrintableChar(b)) {
                    return minus ? -n : n;
                } else {
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
    }
}
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