Cod sursa(job #2866875)

Utilizator AlexBabBabacea Alexandru AlexBab Data 10 martie 2022 05:51:48
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.58 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int NMax = 50005, inf = (1 << 30);
int D[NMax];
bool InCoada[NMax];
int N, M;
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({y, c});
    }
}

void dijkstra(int nodStart)
{
    for(int i = 1; i <= N; i++)
        D[i] = inf;
    D[nodStart] = 0;
    Coada.push(nodStart);
    InCoada[nodStart] = true;
    while(!Coada.empty())
    {
        int nodCurent = Coada.top();
        Coada.pop();
        InCoada[nodCurent] = false;
        for(unsigned int i = 0; i < G[nodCurent].size(); i++)
        {
            int Vecin = G[nodCurent][i].first;
            int Cost = G[nodCurent][i].second;
            if(D[Vecin] > D[nodCurent] + Cost)
                D[Vecin] = D[nodCurent] + Cost;
            if(InCoada[Vecin] == false)
            {
                InCoada[Vecin] = true;
                Coada.push(Vecin);
            }
        }
    }
}

void afiseaza()
{
    for(int i = 2; i <= N; i++)
    {
        if(D[i] != inf)
            fout << D[i] << ' ';
        else
            fout << 0 << ' ';
    }
}

int main()
{
    citeste();
    dijkstra(1);
    afiseaza();
    return 0;
}