Cod sursa(job #1888897)

Utilizator cristicretancristi cretan cristicretan Data 22 februarie 2017 13:34:55
Problema Algoritmul lui Dijkstra Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 1.42 kb
#include <bits/stdc++.h>
#define NMax 50003
#define INF 0x3f3f3f3f
using namespace std;

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

vector<pair<int, int> > G[NMax];
multiset<pair<int, int> > H;
int n, m, x, y, z;
int dist[NMax];

void dijkstra(vector<pair<int, int> > G[NMax], int k)
{
    dist[k] = 0; /// distanta pana la nodul de plecare e 0
    H.insert(make_pair(0, k)); /// pun in multiset costul pana la nodul de plecare (0)
    while(!H.empty()) /// cat timp nu mai sunt costuri
    {
        int nod = (*H.begin()).second; /// dau valoare lui nod cu nod...
        H.erase(H.begin()); /// il scot din multiset
        for(int i = 0; i < G[nod].size(); ++i) /// parcurg vecinii nodului de plecare
            if(dist[G[nod][i].first] > dist[nod] + G[nod][i].second) /// verific daca exista un drum mai bun
        {
            dist[G[nod][i].first] = dist[nod] + G[nod][i].second;
            H.insert(make_pair(dist[G[nod][i].first], G[nod][i].first)); /// fac insert la pereche cu noua distanta si noul nod
        }
    }
}
int main()
{
    f >> n >> m;
    for(int i =1; i <= m; ++i)
    {
         f >> x >> y >> z;
         G[x].push_back(make_pair(y, z));
    }
    memset(dist, INF, sizeof(dist)); /// fac toate distantele infinit
    dijkstra(G, 1);
    for(int i = 2; i <= n; ++i)
        if(dist[i] == INF) g << 0 << " ";
        else g << dist[i] << " ";
    return 0;
}