Cod sursa(job #2416500)

Utilizator pickleVictor Andrei pickle Data 27 aprilie 2019 17:00:56
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.17 kb
// Dijkstra: Priority Queue

#include <stdio.h>
#include <bits/stdc++.h>

#define rep(i, n) for(int i = 0; i < n; i++)
#define Rep(i,a,b) for(int i = a; i < b; i++)

using namespace std;
typedef pair<int, int> pii;
const int INF = 0x3f3f3f3f;
const int Nmax = 50333;

vector<pii> G[Nmax];
int N, M, a, b, c, d[Nmax];
char vis[Nmax];

int main(void) {
  freopen("dijkstra.in", "r", stdin);
  freopen("dijkstra.out", "w", stdout);

  cin >> N >> M;
  rep(i, M) {
    cin >> a >> b >> c;
    --a;
    --b;
    G[a].push_back({c, b}); // {cost, neighbor }
  }
  rep(i, N) { d[i] = INF; }
  priority_queue<pii, vector<pii>, greater<pii> > Q; // order ascending

  d[0] = 0; vis[0] = 1;
  for(pii V: G[0]) {
    Q.push({V.first, V.second}); // ascending by cost - P.second
  }

  while(!Q.empty()) {
    pii V = Q.top(); Q.pop();
    if(vis[V.second])
      continue;

    d[V.second] = V.first;
    vis[V.second] = 1;

    for(pii X: G[V.second]) {
      if (d[X.second] > d[V.second] + X.first) {
        d[X.second] = d[V.second] + X.first;
        Q.push({ d[X.second], X.second });
      }
    }
  }

  Rep(i, 1, N) {
    cout << (d[i] == INF ? 0 : d[i]) << ' ';
  }
  cout << endl;

  return 0;
}