Cod sursa(job #1318767)

Utilizator c0rn1Goran Cornel c0rn1 Data 16 ianuarie 2015 12:33:55
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 kb
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <vector>
#include <bitset>
#define NMAX 100008
#define inf 0x3f3f3f3f

using namespace std;

int n, m, s, b[NMAX];
bitset<NMAX> viz;
queue<int> q;
vector<int> v[NMAX];

void read(){

   int x, y;
   scanf("%d %d %d\n", &n, &m, &s);
   for (int i=0; i<m; i++){
      scanf("%d %d", &x, &y);
      v[x].push_back(y);
   }

}

void bfs(){

   vector<int>::iterator it;
   int nodc;
   memset(b, inf, sizeof b);
   q.push(s);
   viz[s] = 1;
   b[s] = 0;
   while(!q.empty()){

      nodc = q.front();
      q.pop();
      viz[nodc] = 0;
      for (it = v[nodc].begin(); it != v[nodc].end(); it++){
         if (!viz[*it] && b[*it] > b[nodc] + 1){
            viz[*it] = 1;
            b[*it] = b[nodc] + 1;
            q.push(*it);
         }
      }
   }
}

void prnt(){

   for (int i=1; i<=n; i++){
      if (b[i] == inf){
         printf("-1 ");
      }
      else {
         printf("%d ", b[i]);
      }
   }

}

int main()
{
   freopen("bfs.in", "r", stdin);
   freopen("bfs.out", "w", stdout);
   read();
   bfs();
   prnt();

   return 0;
}