Cod sursa(job #383206)

Utilizator ooctavTuchila Octavian ooctav Data 15 ianuarie 2010 23:34:21
Problema Algoritmul Bellman-Ford Scor 35
Compilator cpp Status done
Runda Arhiva educationala Marime 1.68 kb
#include <cstdio>
#include <vector>
#define NMAX 55001
#define POS 500001
#define INF 1000000000
#define CARACTER 101
using namespace std;
void initializare();
void citire();
void rezolvare();
void scrie();
int N,M;
vector<int> G[NMAX],H[NMAX];
int COADA[POS],NR=0;
int VAL[POS];
bool bou=0;

int main()
{
	freopen("bellmanford.in","r",stdin);
	freopen("bellmanford.out","w",stdout);
	initializare();
	citire();
	rezolvare();
	scrie();
	
	return 0;
}

void initializare()
{
	for(int i=1;i<=NMAX;i++)
		VAL[i]=INF;
}

void citire()
{
	int a,val[5],d,bou;
	char ch[CARACTER];
	scanf("%d %d\n",&N,&M);
	for(int i=1;i<=M;i++)
	{
		fgets(ch,CARACTER,stdin);
		d=0;a=0;bou=0;
		for(int k=0; ch[k]!='\n' && ch[k]!=EOF;k++)
			if(ch[k]==' ')
			{
				if(bou==1)
					a=-a,bou=0;
				val[++d]=a,a=0;
			}
			else if(ch[k]=='-')
				bou=1;
			else
				a=10*a+ch[k]-'0';
		if(bou==1)
				a=-a,bou=0;
		val[++d]=a;
		G[val[1]].push_back(val[2]);
		H[val[1]].push_back(val[3]);
	}
		
}

void rezolvare()
{
	vector<int>::iterator it,ih;
	
	for( it=G[1].begin(), ih=H[1].begin(); it!=G[1].end() ;it++,ih++)
	{
		COADA[++NR]=*it;
		VAL[COADA[NR]]=*ih;
	}
	
	for(int i=1;i<=NR;i++)
		for( it=G[COADA[i]].begin(), ih=H[COADA[i]].begin(); it!=G[COADA[i]].end() ;it++,ih++)
			{
				if(VAL[*it]==INF)
					COADA[++NR]=*it;
				if(*ih+VAL[COADA[i]]<VAL[*it])
				{
					VAL[*it]=*ih+VAL[COADA[i]];
					if(*it!=COADA[NR])
						COADA[++NR]=*it;
				}
			}
}

void scrie()
{
	if(VAL[1]<0)
	{
		printf("Ciclu negativ!");
		return;
	}
	
	for(int i=2;i<=N;i++)
	{
		if(VAL[i]==INF)
			printf("%d ",0);
		else
			printf("%d ",VAL[i]);
	}
}