Cod sursa(job #2698194)

Utilizator codustef122Smeu Stefan codustef122 Data 21 ianuarie 2021 12:33:17
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.68 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 inf = (1 << 30);
int N, M;
int D[NMax];
bool InQ[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> Q;

void read()
{
    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 nodeStart)
{
    // initialie distance vector with inf
    for (int i = 1; i <= N; i++)
        D[i] = inf;
    // distance from frst node to itself is 0
    D[nodeStart] = 0;
    
    Q.push(nodeStart);
    InQ[nodeStart] = true;

    while (!Q.empty())
    {
        int nodCurent = Q.top();
        Q.pop();
        InQ[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 (InQ[Vecin] == false)
                {
                    Q.push(Vecin);
                    InQ[Vecin] = true;
                }
            }
        }
    }
}
void show()
{
    for (int i = 2; i <= N; i++)
    {
        if (D[i] != inf)
            fout << D[i] << " ";
        else
            fout << "0 ";
    }
}
int main()
{
    read();
    Dijkstra(1);
    show();
}