Cod sursa(job #1459566)

Utilizator BaweeLazar Vlad Bawee Data 10 iulie 2015 11:26:42
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.28 kb
#include <cstdio>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

int n,m,s;

vector< vector<int> > graf;
vector<int> d;
vector<bool> visited;
queue<int> Q;

void read()
{
    in >> n >> m >> s;

    d.resize(n+1);
    visited.resize(n+1);
    graf.resize(n+1);

    /*for(int i = 0; i <= n; i++)
    {
        vector<int> v;
        graf.push_back(v);
    }*/

    int x,y;
    for(int i = 0; i <= m; i++)
    {
        in >> x >> y;
        graf[x].push_back(y);
    }
}

void bfs(int source)
{
    d[source] = 0;
    Q.push(source);
    visited[source] = true;

    while(!Q.empty())
    {
        int u = Q.front();
        Q.pop();
        for(unsigned int i = 0; i < graf[u].size(); i++)
        {
            int v = graf[u][i];
            if(visited[v] == false)
            {
                d[v] = d[u] + 1;
                Q.push(v);
                visited[v] = true;
            }

        }
    }
}

void write()
{
    for(int i = 1; i <= n; i++)
    {
        if(i != s && d[i] == 0)
            out << -1 <<" ";
        else
            out << d[i] <<" ";
    }
}

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