Cod sursa(job #2170692)

Utilizator george.ursachiUrsachi George george.ursachi Data 15 martie 2018 09:23:47
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include <fstream>
#include <vector>
#include <set>
#include <cstring>

using namespace std;
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

int N,M,dist[50005];
vector< pair<int,int> > v[50005];
set < pair<int,int> >s;
vector< pair<int,int> >::iterator it;
const int INF=0x3f3f3f3f;

void citire()
{
    int x,y,z;
    fin>>N>>M;
    for(int i=1;i<=M;i++)
    {
        fin>>x>>y>>z;
        v[x].push_back(make_pair(y,z));
    }
}

void dijkstra(int nodInitial)
{
    int nod,vecin,cost;
    memset(dist,INF,sizeof(dist));
    dist[nodInitial]=0;
    s.insert(make_pair(0,nodInitial));

    while(!s.empty())
    {
        nod=s.begin()->second;
        s.erase(s.begin());
        for(it=v[nod].begin();it!=v[nod].end();it++)
        {
            vecin=it->first;
            cost=it->second;
            if(dist[vecin]>dist[nod]+cost)
            {
                if(dist[vecin]!=INF)
                    s.erase(s.find(make_pair(dist[vecin],vecin)));
                dist[vecin]=dist[nod]+cost;
                s.insert(make_pair(dist[vecin],vecin));
            }
        }
    }
}

int main()
{
    citire();
    dijkstra(1);
    for(int i=2;i<=N;i++)
    {
        if(dist[i]==INF)fout<<0<<' ';
        else fout<<dist[i]<<' ';
    }
    fin.close();
    fout.close();
    return 0;
}