Cod sursa(job #367882)

Utilizator mihainexMihai Nechita mihainex Data 23 noiembrie 2009 18:15:42
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.86 kb
#include<fstream>
using namespace std;
#define MAX 100001
int n,* a[MAX],s,d[MAX];

void read(){
	ifstream fin("bfs.in");
	int m;
	fin>>n>>m>>s;
    int *grad=new int[n+1];
	for(int i=1;i<=n;i++)
	    grad[i]=0;
	for(;m;m--)
	    {
			int i,j;
			fin>>i>>j;
			grad[i]++;
		}
	fin.close();
	fin.open("bfs.in");
	fin>>n>>m>>s;
	for(int i=1;i<=n;i++)
	{
		a[i]=new int[grad[i]+1];
		a[i][0]=0;
		d[i]=-1;
	}
	delete[] grad;
	for(;m;m--)
	{
		int i,j;
		fin>>i>>j;
		a[i][++a[i][0]]=j;
	}
}
void bfs(){
    int *coada=new int[n+1],st=1,dr=1,k,i;
	coada[1]=s;
	d[s]=0;
	while(st<=dr)
	{
		k=coada[st++];
		for(i=1;i<=a[k][0];i++)
		    if(d[a[k][i]]==-1)
			   {
				   coada[++dr]=a[k][i];
				   d[a[k][i]]=d[k]+1;
				}
	}
}
void write(){
	ofstream fout("bfs.out");
	for(int i=1;i<=n;i++)
	    fout<<d[i]<<" ";
	fout.close();
}

int main()
{
	read();
	bfs();
	write();
    return 0;
}