Cod sursa(job #2788091)

Utilizator juniorOvidiu Rosca junior Data 24 octombrie 2021 21:56:15
Problema Algoritmul lui Dijkstra Scor 90
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.5 kb
#include <fstream>
#include <queue>
#include <tuple>
#include <vector>

#define MARE 100000000
#define LIMITA 50001

using namespace std;

struct VECIN {
  int nn;
  unsigned short int cost;
};

int i, n, m, x, y, s, d[LIMITA];
unsigned short int c;
vector<VECIN> vv[LIMITA];
priority_queue<pair<int, unsigned short int>> pq;  // distanta, numarul nodului
bool sel[LIMITA];
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");

void dijkstra(int s) {
  int nmin, dn;
  for (i = 2; i <= n; i++)
    d[i] = MARE;  // Initializam distanta fata de sursa.
  d[s] = 0;
  pq.push(make_pair(0, 1));  // Punem sursa in coada
  while (not pq.empty()) {   // Selectam cate un nod.
    nmin = pq.top().second;
    pq.pop();
    sel[nmin] = true;          // retinem nodul care ne da minimul [nmin]
    for (auto v : vv[nmin]) {  // doar vecinii lui nmin [*]
      if (not sel[v.nn]) {
        dn = d[nmin] + v.cost;  // calculam distanta noua, folosind nmin.
        if (d[v.nn] > dn) {     // Daca am gasit un lant mai scurt prin nmin,
          d[v.nn] = dn;         // actualizam distanta de la sursa la nv.
          pq.push(make_pair(-dn, v.nn));  // Punem nodul in coada.
        }
      }
    }
  }
}

int main() {
  fin >> n >> m;
  for (i = 1; i <= m; i++) {
    fin >> x >> y >> c;
    vv[x].push_back({y, c});  // vectori de vecini
  }
  dijkstra(1);
  for (i = 2; i <= n; i++) {
    if (d[i] == MARE)
      fout << "0 ";
    else
      fout << d[i] << ' ';
  }
  return 0;
}