Cod sursa(job #2533011)

Utilizator uclaudiu7Ursescu Claudiu uclaudiu7 Data 28 ianuarie 2020 18:06:30
Problema Algoritmul lui Dijkstra Scor 20
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.59 kb
#include <iostream>
#include <fstream>
#include <queue>
#include <vector>

using namespace std;

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

const int oo = (1<<30);
const int NMAX = 50001;

int n, m;
int D[NMAX];

vector < pair < int, int > > G[NMAX];
vector < bool > visited(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;
    int i, x, y, c;
    for(i = 1; i <= m; ++i)
    {
        fin >> x >> y >> c;
        G[x].push_back(make_pair(y,c));
    }
}

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

    D[startNode] = 0;
    q.push(startNode);
    visited[startNode] = true;

    while(!q.empty())
    {
        int node = q.top();
        q.pop();
        visited[node] = false;

        for(size_t i = 0; i < G[node].size(); ++i)
        {
            int vecin = G[node][i].first;
            int cost = G[node][i].second;

            if(D[node] + cost < D[vecin])
            {
                D[vecin] = D[node] + cost;
                if(visited[vecin] == false)
                {
                    q.push(vecin);
                    visited[vecin] = true;
                }
            }
        }
    }
}

void Write()
{
    int i;
    for(i = 2; i <= n; ++i)
        if(D[i] != oo)
            fout << D[i] << " ";
        else
            fout << -1;
}

int main()
{
    Read();
    Dijkstra(1);
    Write();
    return 0;
}