Cod sursa(job #659805)

Utilizator alexdmotocMotoc Alexandru alexdmotoc Data 11 ianuarie 2012 00:04:12
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.25 kb
#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>

using namespace std;

#define maxN 250005
#define INF 0x3f3f3f3f

vector < pair <int , int> > lista[maxN];
queue <int> Q;

int cost[maxN] , cost_aux , noduri[maxN];
int N , M;

int main ()
{
	freopen ("bellmanford.in" , "r" , stdin);
	freopen ("bellmanford.out" , "w" , stdout);
	
	scanf ("%d %d" , &N , &M);
	
	int a , b , c;
	
	for (int i = 1 ; i <= M ; ++i)
	{
		scanf ("%d %d %d" , &a , &b , &c);
		
		lista[a].push_back (make_pair (b , c));
	}
	
	for (int i = 1 ; i <= N ; ++i)
		cost[i] = INF;
	
	int nod;
	
	Q.push (1);
	cost[1] = 0;
	
	while (!Q.empty ())
	{
		nod = Q.front ();
		
		for (unsigned i = 0 ; i < lista[nod].size () ; ++i)
		{
			
			cost_aux = cost[nod] + lista[nod][i].second;
			
			if (cost[lista[nod][i].first] > cost_aux)
			{
				cost[lista[nod][i].first] = cost_aux; 
				noduri[lista[nod][i].first]++;
				
				if (noduri[lista[nod][i].first] > N)
				{
					printf ("Ciclu negativ!");
					return 0;
				}
				
				Q.push (lista[nod][i].first);
			}
		}
		
		Q.pop ();
	}
	
	for (int i = 2 ; i <= N ; ++i)
		if (cost[i] != INF)
			printf ("%d " , cost[i]);
		
		else printf ("0 ");
	
	return 0;
}