Cod sursa(job #1537651)

Utilizator tudorcomanTudor Coman tudorcoman Data 27 noiembrie 2015 18:32:00
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.17 kb
#include <cstring>
#include <cstdio>
#include <vector>
#include <queue>
using namespace std;

const int maxN = 50000;
const int maxM = 250000;
const int infi = 1 << 30;
int N, M, d[maxN], f[maxN];

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

int main() {
  freopen("bellmanford.in", "r", stdin);
  freopen("bellmanford.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));
  }

  queue<int> C;
  for(register int i = 2; i <= N; ++ i)
    d[i] = infi;

  d[1] = d[0] = 0;
  C.push(1);
  while(!C.empty()) {
    int x = C.front(); C.pop();

    for(auto it = G[x].begin(); it != G[x].end(); ++ it) {
      int its = it->second, itf = it->first;
      if(d[x] + its < d[itf]) {
        d[itf] = d[x] + its;
        ++ f[itf];
        if(f[itf] > N) {
          puts("Ciclu negativ!");
          return 0;
        }
        C.push(it->first);
      }
    }
  }

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