Cod sursa(job #1415503)

Utilizator Denisa13Stefan Denisa Denisa13 Data 4 aprilie 2015 21:27:20
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.41 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

#define NMAX 50005
#define MMAX 250005

using namespace std;

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

vector <pair<int,int> > G[NMAX];
priority_queue <pair<int,int> > pq;
int n,m, sol[NMAX];
bool viz[NMAX];

void dijkstra(int nod)
{
    while(pq.empty()==0)//cat timp coada nu e goala
    {
        viz[nod]=1;
        for(int i=0;i<G[nod].size();i++)
        {
            int cost=sol[nod]+G[nod][i].second; //costul unui nod=costul tatalui + costul muchiei dintre ei
            if(sol[G[nod][i].first]>cost)// daca e mai mic ca ce era inainte inregistrat, modificam in solutii si adaugam in coada
            {
                sol[G[nod][i].first]=cost;
                pq.push(make_pair(-cost,G[nod][i].first));
            }
        }
        if(pq.top().second==nod)
            pq.pop(); //scot din coada de prioritati nodul de cost minim
        nod=pq.top().second;

    }
}

int main()
{
    int i,x,y,cost;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>cost;
        G[x].push_back(make_pair(y,cost));
    }
    for(i=1;i<=n;i++)
        if(i==1)
            sol[i]=0;
        else sol[i]=1<<30;
    pq.push(make_pair(0,1));
    dijkstra(1);
    for(i=2;i<=n;i++)
        if(viz[i]==0)
            sol[i]=0;
    for(i=2;i<=n;i++)
        g<<sol[i]<<' ';
    return 0;
}