Cod sursa(job #228445)

Utilizator M@2Te4iMatei Misarca M@2Te4i Data 7 decembrie 2008 11:39:28
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.85 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

int w[100002],m,n,s;
vector <int> v[100002];
queue <int> q;

ifstream fin ("bfs.in");
ofstream fout ("bfs.out");

void citire()
{
    int x,y;
    fin >> n >> m >> s;
    for (int i=0; i<m; i++)
    {
        fin >> x >> y;
        v[x].push_back(y);
    }
}

void bfs()
{
    int a;
    while (!q.empty())
    {
        a=q.front();
        q.pop();
        for (vector <int> ::iterator it=v[a].begin(); it!=v[a].end(); it++)
            if (w[*it]==-1)
            {
                q.push(*it);
                w[*it]=w[a]+1;
            }
    }
}

int main()
{
    memset(w, 0xff, sizeof(w));
    citire();
    w[s]=0;
    q.push(s);
    bfs();
    for (int i=1; i<=n; i++)
        fout << w[i] << " ";
    return 0;
}