Cod sursa(job #2072382)

Utilizator deleted_fb9d5fb04f7b88d9DELETED deleted_fb9d5fb04f7b88d9 Data 21 noiembrie 2017 20:03:50
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 1.41 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define NM 50001
#define INF 2000000000
using namespace std;
ifstream fin ("dijkstra.in");
ofstream fout ("dijkstra.out");

struct arc {
    int y, c;
};

int d[NM], n, m, p = 1;
bool inq[NM];

struct compar {
    bool operator() (int x, int y) {
        return d[x] > d[y];
    }
};

vector <arc> G[NM];
priority_queue <int, vector <int>, compar> q;

void citire () {
    arc u;
    int x, y;

    fin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        fin >> x >> u.y >> u.c;
        G[x].push_back(u);
    }
}

void dijkstra () {
    int i, im;
    int y, c, lg;

    for (i = 1; i <= n; ++i) d[i] = INF;
    d[p] = 0;
    q.push(p);
    inq[p] = true;

    while (!q.empty()) {
        im = q.top();
        q.pop();
        inq[im] = false;
        for (i = 0; i < G[im].size(); ++i) {
            y = G[im][i].y;
            c = G[im][i].c;
            lg = d[im] + c;
            if (lg < d[y]) {
                d[y] = lg;
                if (!inq[y]) {
                    q.push(y);
                    inq[y] = true;
                }
            }
        }
    }
}

void afisare () {
    for (int i = 2; i <= n; ++i)
        if (d[i] != INF) fout << d[i] << ' ';
        else fout << -1 << ' ';
}

int main() {
    citire();
    dijkstra();
    afisare();
    return 0;
}