Cod sursa(job #1429779)

Utilizator MarianMMorosac George Marian MarianM Data 7 mai 2015 07:50:02
Problema Algoritmul lui Dijkstra Scor 0
Compilator java Status done
Runda Arhiva educationala Marime 2.2 kb
import java.io.*;
import java.util.*;

public class Main {
    static int INF = 250000001;

    static int n , m;

    public static void main(String[] args) {
        Scanner fin = new Scanner(System.in);
        /* FILE INPUT*/
        try {
            fin = new Scanner(new File("dijkstra.in"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        /* FILE OUTPUT*/
        PrintStream out = null;
        try {
            out = new PrintStream(new FileOutputStream("dijkstra.out"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        System.setOut(out);

        n = fin.nextInt();
        m = fin.nextInt();

        // list of all Vertices / Nodes
        ArrayList<Node> graph= new ArrayList<Node>();
        for (int i=0; i<=n; i++) graph.add(new Node(i));

        // Reading Vertices and Weights
        int a, b, c;
        for (int i=0; i<m; i++){
            a = fin.nextInt();
            b = fin.nextInt();
            c = fin.nextInt();

            graph.get(a).adjList.put(b, c);
        }

        // Djikstra
        PriorityQueue<Node> Q = new PriorityQueue<Node>();

        // initialise nodes in Queue
        graph.get(1).dist = 0;
        for (int i=1; i <= n; i++) Q.offer(graph.get(i));

        while(!Q.isEmpty()){
            Node parent = graph.get(Q.poll().nr);

            for (Map.Entry<Integer, Integer> childNr : parent.adjList.entrySet()){
                Node kid = graph.get(childNr.getKey());
                if (kid.dist > parent.dist + childNr.getValue()){
                    Q.remove(kid);
                    kid.dist = parent.dist + childNr.getValue();
                    Q.add(kid);
                }
            }
        }

        for(int i=2; i<=n; i++) System.out.print(graph.get(i).dist + " ");
    }
}

class Node implements Comparable<Node>{
    public Map<Integer, Integer> adjList = new HashMap<Integer, Integer>();
    public int dist = Main.INF;
    public int nr = 0;

    public Node (int x){
        this.nr = x;
    }

    public int compareTo(Node o) {
        return Integer.compare(this.dist, o.dist);
    }
}