Cod sursa(job #560859)

Utilizator mihaimoldovanMihai Moldovan mihaimoldovan Data 18 martie 2011 18:31:44
Problema BFS - Parcurgere in latime Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include<fstream>
#include<vector>
using namespace std;

#define nn 100001
#define pb push_back
#define infinit 1<<20
vector<int>g[nn];
int n,m,s,d[nn];
void citire(){
    int a,b;
    ifstream fin("bfs.in");
    fin>>n>>m>>s;
    for(;m;--m){
        fin>>a>>b;
        g[a].pb(b);//graf orientat
    }
}
void afisare(){
    FILE *f=fopen("bfs.out","w");
    for(int i=1;i<=n;++i)
        if(d[i]!=infinit)
            fprintf(f,"%d ",d[i]);
        else
            fprintf(f,"-1 ");
}
void bfs(){
    for(int i=1;i<=n;++i)
        d[i]=infinit;
    int coada[nn],st,dr,i;
    st=dr=1;
    d[s]=0;
    coada[st]=s;
    while(st<=dr){
        int k=coada[st++];
        for(i=0;i<g[k].size();++i)
            {
                int kk=g[k][i];
                coada[++dr]=kk;
                if(d[k]+1<d[kk])
                    d[kk]=d[k]+1;
            }
    }
}
int main(){
    citire();
    bfs();
    afisare();
    return 0;
}