Bfs algorithm

bfs.py

import Queue

Grafo = { 0 : [1, 3],
          1 : [0, 2],
          2 : [1, 3],
          3 : [0, 2] 
}

def queue_insert(q, v):
    q.insert(0, v)
    

def bfs(grafo, start):
  
  mark = [ False for _ in range(4)]
  l = [None for _ in range(4)]
  p = [None for _ in range(4)]
  
  queue = []
  queue_insert(queue, start)
  
  
  l[start] = 0
  mark[start] = True
  while queue != []:
      u = queue.pop()
      for v in grafo[u]:
          if mark[v] == False:
              mark[v] = True
              queue_insert(queue, v)
              l[v] = l[u] + 1
              p[v] = u
  return p, l

#print bfs(Grafo, 0)