Cod sursa(job #388619)

Utilizator AndreyPAndrei Poenaru AndreyP Data 30 ianuarie 2010 15:46:25
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.31 kb
#include<stdio.h>
#include<string.h>
#include<vector>
#include<queue>
#include<bitset>
using namespace std;
#define pb push_back
#define N 50010
#define pii pair<int,int>
#define fs first
#define sc second
#define mp make_pair
const int inf=1<<30;
int n,m;
vector< pii > a[N];
int d[N];
int *nr[N];
bitset<N> inq;
queue<int> q;
inline void citire()
{
	scanf("%d%d",&n,&m);
	int x,y,z;
	for(int i=0; i<m; ++i)
	{
		scanf("%d%d%d",&x,&y,&z);
		a[x].pb(mp(y,z));
	}
}
inline bool bellmanFord()
{
	for(int i=1; i<=n; ++i)
	{
		nr[i]=new int[a[i].size()];
		memset(nr[i],0,a[i].size()*sizeof(int));
		d[i]=inf;
	}
	d[1]=0;
	inq[1]=1;
	q.push(1);
	int now,next,cost;
	while(!q.empty())
	{
		now=q.front();
		q.pop();
		inq[now]=0;
                for(size_t i=0,lim=a[now].size(); i<lim; ++i)
		{
			next=a[now][i].fs;
			cost=a[now][i].sc;
			if(d[now]+cost<d[next])
			{
				++nr[now][i];
				if(nr[now][i]==n)
					return true;
				d[next]=d[now]+cost;
				if(inq[next]==0)
				{
					q.push(next);
					inq[next]=1;
				}
			}
		}
	}
	return false;
}
inline void scrie()
{
	for(int i=2; i<n; ++i)
		printf("%d ",d[i]);
	printf("%d\n",d[n]);
}
int main()
{
	freopen("bellmanford.in","r",stdin);
	freopen("bellmanford.out","w",stdout);
	citire();
	if(bellmanFord())
	{
		fputs("Ciclu negativ!",stdout);
		return 0;
	}
	scrie();
	return 0;
}