Cod sursa(job #3120967)

Utilizator unomMirel Costel unom Data 9 aprilie 2023 23:07:56
Problema Algoritmul lui Dijkstra Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.5 kb
#include <fstream>
#include <set>
#include <vector>

using namespace std;

ifstream f("dijkstra.in");
ofstream g("dijkstra.out");

struct nod
{
    vector <pair<int, int>> vec;
};
nod v[50005];
int d[50005];
multiset <pair<int, int>> s;
int n, m;

int main()
{

    int INF = (1 << 30) - 1;

    f>>n>>m;
    int st, dr, c;
    for(int i = 1; i<=n; i++)
    {
        f>>st>>dr>>c;
        v[st].vec.push_back({dr, c});
    }

    for(int i = 2; i<=n; i++)
    {
        d[i] = INF;
    }
    for(int i = 0; i<v[1].vec.size(); i++)
    {
        d[v[1].vec[i].first] = v[1].vec[i].second;
        s.insert({v[1].vec[i].second, v[1].vec[i].first});
    }

    int cost, nd;
    while(!s.empty())
    {
        cost = (*s.begin()).first;
        nd = (*s.begin()).second;
        s.erase(s.begin());

        for(int i = 0; i<v[nd].vec.size(); i++)
        {
            if(d[v[nd].vec[i].first] > cost + v[nd].vec[i].second)
            {
                if(d[v[nd].vec[i].first] != INF)
                {
                    s.erase(s.find({d[v[nd].vec[i].first], v[nd].vec[i].first}));
                }
                d[v[nd].vec[i].first] = cost + v[nd].vec[i].second;
                s.insert({d[v[nd].vec[i].first], v[nd].vec[i].first});
            }
        }
    }

    for(int i = 2; i<=n; i++)
    {
        if(d[i] == INF)
        {
            g<<0<<" ";
        }
        else
        {
            g<<d[i]<<" ";
        }
    }


    return 0;
}