Cod sursa(job #2766666)

Utilizator NanuGrancea Alexandru Nanu Data 2 august 2021 18:36:21
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.38 kb

#include <fstream>
#include <vector>
#include <set>

using namespace std;

ifstream cin("dijkstra.in");
ofstream cout("dijkstra.out");

#define DIM 50001
#define INF (1 << 28)

vector <pair<int, int>> v[DIM];
int n, m, x, y, c, dist[DIM];

static inline void Dijkstra(int k) {
    for(int i = 1; i <= n; i++)
        dist[i] = INF;
    dist[k] = 0;    ///distanta pana la el e 0;

    set<pair<int, int>> d; ///retin costul si nodul pentru a fi sortate crescator dupa cost;
    d.insert({0, k});   ///distanta si nodul;

    while(!d.empty()) {
        int node = d.begin()->second;
        d.erase(d.begin());
        for(auto e : v[node]) { ///unde pot merge din nodul actual;
            int nod = e.first;
            int cost = e.second;
            if(dist[nod] > cost + dist[node]) { ///daca am un drum mai bun;
                if(dist[nod] != INF)
                    d.erase(d.find({dist[nod], nod}));
                dist[nod] = cost + dist[node];  ///retin costul minim
                d.insert({dist[nod], nod});     ///il adaug in set;
            }
        }
    }
}

int main() {
    cin >> n >> m;
    for(int i = 1; i <= m; i++) {
        cin >> x >> y >> c;
        v[x].push_back({y, c}); ///destinatie si cost;
    }

    Dijkstra(1);
    for(int i = 2; i <= n; i++)
        cout << (dist[i] == INF ? 0 : dist[i]) << " ";

    return 0;
}