Cod sursa(job #3184095)

Utilizator monica_LMonica monica_L Data 14 decembrie 2023 12:29:40
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.21 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define nmax 50001
#define inf 1e9
#define PII pair<int,int>
using namespace std;

ifstream f("dijkstra.in");
ofstream g("dijkstra.out");
vector<PII> v[nmax];
priority_queue<PII,vector<PII>,greater<PII> >h;
int d[nmax], n, m;

void dijkstra(int ns)
{
    int i, nod, vecin, cost;

    for(i=1; i<=n; i++) d[i] = inf;
    d[ns] = 0;
    h.push({0,ns});

    while(!h.empty())
    {
        nod = h.top().second;
        cost = h.top().first;
        h.pop();

        if(d[nod] != cost) continue; // daca distanta minima pana la nod a fost deja actualizata

        for(i=0; i<v[nod].size(); i++)
        {
            vecin = v[nod][i].second;
            cost  = v[nod][i].first;
            if(d[nod] + cost < d[vecin])
            {
                d[vecin] = d[nod] + cost;
                h.push({d[vecin],vecin});
            }
        }
    }
}
int main()
{
    int i, a, b, c;;

    f>>n>>m;
    for(i=1; i<=m; i++)
    {
        f>>a>>b>>c;
        v[a].push_back({c,b});
    }

    dijkstra(1);

    for(i=2; i<=n; i++)
        if(d[i]==inf) g<<0<<" ";
        else g<<d[i]<<" ";

    return 0;
}