Cod sursa(job #1519934)

Utilizator tc_iuresiures tudor-cristian tc_iures Data 8 noiembrie 2015 08:25:59
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.02 kb
//vezi http://www.infoarena.ro/problema/bfs
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

const int Nmax = 100005;

vector<int> G[Nmax];

int N, M, S;
int D[Nmax];

void read()
{
   ifstream f("bfs.in");
   f >> N >> M >> S;
   int x, y;
   for(int i = 0; i < M; i ++)
   {
      f >> x >> y;
      G[x].push_back(y);
   }
   f.close();
}

void BFS(int k)
{
   D[k] = 0;
   queue<int> Q;
   Q.push(k);
   while(!Q.empty())
   {
      int x = Q.front();
      Q.pop();
      for(int i = 0; i < G[x].size(); i ++)
      {
         int Ngh = G[x][i];
         if(D[Ngh] == -1)
         {
            D[Ngh] = D[x] + 1;
            Q.push(Ngh);
         }
      }
   }
}

void print()
{
   ofstream g("bfs.out");
   for(int i = 1; i <= N; i ++)
   {
      g << D[i] << " ";
   }
   g.close();
}

int main()
{
    read();
    for(int i = 1; i <= N; i ++)
    {
      D[i] = -1;
    }
    BFS(S);
    print();
    return 0;
}