Cod sursa(job #2494866)

Utilizator cristiifrimIfrim Cristian cristiifrim Data 18 noiembrie 2019 17:23:55
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.49 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

const int nmax = 50001, oo = (1 << 31) - 1;

ifstream f("dijkstra.in");
ofstream g("dijkstra.out");

int n, m, dist[nmax], start;
bool inCoada[nmax];

vector < pair <int, int > > G[nmax];

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

priority_queue < int, vector < int >, test > q;

void citire() {
    f >> n >> start;
    int x, y, c;
    while(f >> x >> y >> c) {
        G[x].push_back(make_pair(y, c));
        //G[y].push_back(make_pair(x, c));
    }
}

void dijkstra(int x) {
    for(int i = 1; i <= n; ++i)
        dist[i] = oo;
    dist[x] = 0;
    q.push(x);
    inCoada[x] = true;
    while(!q.empty()) {
        int y = q.top();
        q.pop();
        inCoada[y] = false;
        for(size_t i = 0; i < G[y].size(); ++i) {

            int vecin = G[y][i].first, cost = G[y][i].second;
            if(dist[y] + cost < dist[vecin]) {
                dist[vecin] = dist[y] + cost;
                if(inCoada[vecin] == false)
                    q.push(vecin);
                    inCoada[vecin] = true;
            }
        }
    }
}

void afisare() {
    for(int i = 2; i <= n; ++i)
        if(dist[i] == oo)
            g << 0 << ' ';
        else
            g << dist[i] << ' ';
}

int main()
{
    citire();
    dijkstra(1);
    afisare();
    g.close();
    f.close();
    return 0;
}