Cod sursa(job #505823)

Utilizator mytzuskyMihai Morcov mytzusky Data 4 decembrie 2010 10:26:29
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.01 kb
#include <iostream>
#include <fstream>

using namespace std;


int st[1000001],lg[100001],viz[100001];
int n,m,s;

struct nod{
    int inf;
    nod *urm;
} ;
nod *g[100001];

void add(int x,int y)
{
    nod *aux = new nod;
    aux->inf=y;
    aux->urm=g[x];
    g[x]=aux;

}

void citire()
{
    ifstream f("bfs.in");
    f>>n>>m>>s;
    for(int i=0;i<m;i++)
    {
        int x,y;
        f>>x>>y;
        add(x,y);
    }
}

void bfs(int x)
{
    viz[x]=1;
    st[0]=x;
    int sf=1;
    for(int i=0;i<sf;i++)
        for(nod *p=g[st[i]];p;p=p->urm)
            if(! viz[p->inf])
            {
                viz[p->inf]=1;
                st[sf++]=p->inf;
                lg[p->inf]=lg[st[i]]+1;
            }
}

void afisare()
{
    ofstream g("bfs.out");
    for(int i=1;i<=n;i++)
    {
        if(!lg[i] && i!=s)
            g<<-1<< " ";
        else
            g<<lg[i]<<" ";
    }
}

int main()
{
    citire();
    bfs(s);
    afisare();
    return 0;
}