Cod sursa(job #2422568)

Utilizator mihaibisoceanuBisoceanu Mihai Cosmin mihaibisoceanu Data 19 mai 2019 11:29:33
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.37 kb
#include <iostream>
#include<fstream>
#include<vector>
#include<queue>
#define N 50001
using namespace std;
ifstream f("dijkstra.in");
ofstream g("dijkstra.out");
vector<pair<int,int> > G[N];

int oo=20001;
int D[N];
int n,m;

void citire()
{
    f>>n>>m;
    oo=oo*n;
    for(int i=0;i<m;i++)
    {
        int a,b,c;
        f>>a>>b>>c;
        G[a].push_back(make_pair(b,c));
    }
}

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

priority_queue<pair<int,int> > q;
bool inq[N]={false};

void Dijkstra(int sursa)
{
    for(int i=1;i<=n;i++)
        D[i]=oo;

    D[sursa]=0;
    q.push(make_pair(-D[sursa],sursa));
    inq[sursa]=1;
    while(!q.empty())
    {
        int nod=q.top().second;
        int dist=-q.top().first;
        q.pop();

        if(dist!=D[nod])
            continue;
        for(int i=0;i<G[nod].size();i++)
        {
            int vecin,cost;
            vecin=G[nod][i].first;
            cost=G[nod][i].second;
            if(D[nod]+cost<D[vecin])
            {
                D[vecin]=D[nod]+cost;
                q.push(make_pair(-D[vecin],vecin));


            }
        }
    }
}
int main()
{
    citire();
    Dijkstra(1);
    for(int i=2;i<=n;i++)
        if(D[i] == oo)
            g<<0<<" ";
        else
            g<<D[i]<<" ";
    return 0;
}