Cod sursa(job #1187203)

Utilizator alevasluialeHuhurez Marius alevasluiale Data 17 mai 2014 20:48:14
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.08 kb
#include <fstream>
#include <bitset>
#include <vector>
#include <queue>
using namespace std;
const int nmax=100001;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
vector<int> x[nmax];
vector <int>::iterator it;
int v[nmax];
bitset<nmax> viz;
struct nr
{
    int pr,cost;
};
queue<nr>coada;
int main()
{
    int n,m,s,i,k,y,r=1;
    fin>>n>>m>>s;
    for(i=1;i<=m;i++)
    {
        fin>>k>>y;
        x[k].push_back(y);
    }
    nr pas;
    pas.pr=s;pas.cost=0;
    coada.push(pas);
    while(r<m&&coada.size())
    {
        for(it=x[coada.front().pr].begin();it!=x[coada.front().pr].end();it++)
        {
            if(viz[*it]==0&&*it!=s)
            {
            pas.pr=*it;
            pas.cost=coada.front().cost+1;
            coada.push(pas);
            viz[*it]=1;
            if(pas.cost<v[*it]||v[*it]==0) v[*it]=pas.cost;
            r++;
            }
        }
        coada.pop();
    }
    for(i=1;i<=n;i++)
    {
        if(v[i]==0&&i!=s) fout<<-1<<" ";
        else if(i==s) fout<<0<<" ";
        else fout<<v[i]<<" ";
    }
}