Cod sursa(job #554176)

Utilizator unknownliviuMaria Liviu Valentin unknownliviu Data 14 martie 2011 17:43:34
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.07 kb
#include<queue>
#include<fstream>
#include<vector>
using namespace std;
ifstream in("bellmanford.in");
ofstream out("bellmanford.out");
const int N=50050;
const int INF=10000000;
vector<int>a[N],c[N];
int n,m;
int d[N],t[N];
bool viz[N];
queue<int>coada;
void read()
{
	int x,y,z;
	in>>n>>m;
	for(int i=1;i<=m;i++)
	{
		in>>x>>y>>z;
		a[x].push_back(y);
		c[x].push_back(z);
	}
}
void init()
{
	for(int i=0;i<=n;i++)
		d[i]=INF;
}
bool belford(int param)
{
	int x,r,cost;
	bool k=1;
	init();
	coada.push(param);
	viz[param]=1;
	d[param]=0;
	while(k==1 && !coada.empty())
	{
		r=coada.front();
		coada.pop();
		for(unsigned int i=0;i<a[r].size();i++)
		{
			x=a[r][i];
			cost=c[r][i];
			viz[r]=false;
			
			if(d[r]+cost<d[x])
			{
				d[x]=d[r]+cost;
				if(!viz[x])
				{
					viz[x]=true;
					t[x]++;
					if(t[x]>n-1)
						k=false;
					coada.push(x);
				}
			}
		}
	}
	return k;
}
int main()
{
	read();
	if(belford(1))
		for(int i=2;i<=n;i++)
			out<<d[i]<<" ";
	else
		out<<"Ciclu negativ!";
	return 0;
}