Cod sursa(job #1401660)

Utilizator Coman95coman cosmin Coman95 Data 26 martie 2015 02:23:25
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.08 kb
#include<fstream>
#include<queue>
#include<vector>
#include<iostream>
using namespace std;

#define NMAX 50001

queue<int> Q;
vector<int> d;
vector<pair<int, int> > g[NMAX];
int n, m, minim = 0;

ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");

int BF();

int main()
{
	int x, y, c;
	fin >> n >> m;
	d.resize(n + 1, 0x3f3f3f3f);
	for (int i = 1; i <= m; ++i)
	{
		fin >> x >> y >> c;
		if (c < 0)
			minim += c;
		g[x].push_back(make_pair(c, y));
	}
	if (BF() < 0)
		fout << "Ciclu negativ!";
	else
	for (int i = 2; i <= n; ++i)
		fout << d[i] << ' ';
	fin.close();
	fout.close();
	return 0;
}

int BF()
{
	int x;
	d[1] = 0;
	Q.push(1);
	while (!Q.empty())
	{
		x = Q.front();
		Q.pop();
		if (d[x] < minim)
			return -1;
		for (vector<pair<int, int> >::iterator it = g[x].begin(); it != g[x].end(); ++it)
		{
			//cout << it->second << ' ' << it->first << '\n';
			if (d[it->second] > d[x] + it->first)
			{
				d[it->second] = d[x] + it->first;
				Q.push(it->second);
			}
		}
		if (d[x] < minim)
			return -1;
	}
	return 1;
}