Cod sursa(job #1539906)

Utilizator tudorcomanTudor Coman tudorcoman Data 1 decembrie 2015 19:38:27
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <cstring>
#include <cstdio>
#include <vector>
#include <queue>
using namespace std;

const int maxN = 50000;
const int maxM = 250000;
const int infi = 0x3f3f3f3f;
int N, M, d[maxN];

typedef pair<int, int> muchie; /// first = nodul, second = lungimea
vector<muchie> G[maxN + 1];

void reset() {
  for(register int i = 2; i <= N; ++ i)
    if(d[i] == infi)
      d[i] = 0;
}

void dijkstra(int start = 1) {
  priority_queue<muchie, vector<muchie>, greater<muchie>> H;
  for(register int i = 2; i < maxN; ++ i)
    d[i] = infi;

  H.push(make_pair(0, start));

  while(!H.empty()) {
    int length = H.top().first, nod = H.top().second;
    H.pop();
    if(d[nod] == length) {
      for(auto it = G[nod].begin(); it != G[nod].end(); ++ it) {
        if(d[nod] + it->second < d[it->first]) {
          d[it->first] = d[nod] + it->second;
          H.push(make_pair(d[it->first], it->first));
        }
      }
    }
  }
  reset();
}

int main() {
  freopen("dijkstra.in", "r", stdin);
  freopen("dijkstra.out", "w", stdout);
  scanf("%d %d", &N, &M);
  for(register int i = 1; i <= M; ++ i) {
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);
    G[a].push_back(make_pair(b, c));
  }

  dijkstra();
  for(register int i = 2; i <= N; ++ i)
    printf("%d ", d[i]);
  printf("\n");
  return 0;
}