Cod sursa(job #1350810)

Utilizator ooptNemes Alin oopt Data 20 februarie 2015 22:58:19
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
// bellmanford
#include <iostream>
#include <queue>
#include <fstream>
#include <vector>

#define NMax 100005
#define inf (1<<30)+100
#define pb push_back

using namespace std;

ofstream g("bellmanford.out");

int n, m;
vector<int> V[NMax];
vector<int> C[NMax];
int dist[NMax];
bool viz[NMax];
queue<int> q;

void read() {
	ifstream f("bellmanford.in");

	f>>n>>m;
	for (int i=1;i<=m;i++) {
		int a, b, c;
		f>>a>>b>>c;
		V[a].pb(b);
		C[a].pb(c);
	}

	f.close();
}

void solve() {

	int pas = 0;

	dist[1] = 0;
	for (int i=2;i<=n;i++) dist[i] = inf;

	q.push(1);
	while (!q.empty() && pas <= (long long)n*m) {
		int nod = q.front();
		q.pop();
		pas++;
		viz[nod] = false;

		for (int i=0;i<V[nod].size();i++) {
			int vecin = V[nod][i];
			if (dist[nod] + C[nod][i] < dist[vecin]) {
				dist[vecin] = dist[nod] + C[nod][i];
				if (!viz[vecin]) {
					viz[vecin] = true;
					q.push(vecin);
				}
			}
		}
	}
}

void print() {
	ifstream f("bellmanford.in");
	f>>n>>m;
	for (int i=1;i<=m;i++) {
		int x,y,c;
		f>>x>>y>>c;
		if (dist[x] + c < dist[y]) {
			g<<"Ciclu negativ\n";
			return;
		}
	}
	for (int i=2;i<=n;i++)
		g<<dist[i]<<' ';
}

int main() {

	read();
	solve();
	print();

	g.close();
	return 0;
}