Mai intai trebuie sa te autentifici.

Cod sursa(job #2239271)

Utilizator CatincaBCatinca Balinisteanu CatincaB Data 10 septembrie 2018 13:53:44
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.56 kb
#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
using namespace std;
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

const int NMax=50005;
const int oo=(1<<30);
int N,M;
int d[NMax];
bool incoada[NMax];

vector < pair < int,int > > g[NMax];

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

priority_queue < int,vector < int >,compara> coada;

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

void afiseaza()
{
    for(int i=3;i<=N;i++)
    {
        if(d[i]!=oo)
            fout<<d[i]<<" ";
        else
            fout<<"0 ";
    }
}

void dijkstra(int nodstart)
{
    for(int i=1;i<=N;i++)
        d[i]=oo;
    d[nodstart]=0;
    coada.push(nodstart);
    incoada[nodstart]=true;
    while(!coada.empty())
    {
        int nodcurent=coada.top();
        coada.pop();
        incoada[nodcurent]=false;

        for(size_t i=0; i<g[nodcurent].size(); i++)
        {
            int vecin=g[nodcurent][i].first;
            int cost=g[nodcurent][i].second;
            if(d[nodcurent]+cost<d[vecin])
            {
                d[vecin]=d[nodcurent]+cost;
                if(incoada[vecin]==false)
                {
                    coada.push(vecin);
                    incoada[vecin]=true;
                }
            }
        }
    }
}
int main()
{
    citeste();
    dijkstra(1);
    afiseaza();
    return 0;
}