Breadth-First Search

function BreadthFirstSearch(G,source){
  for each vertex u in (G.V - {source}) {
      u.color = white
      u.d = infinity
      u.phi = NaN
  }
  source.color = grey
  source.d = 0
  source.phi = NaN
  Q = new empty queue
  Enqueue(Q, source)
  //Step = 0
  while Q is not empty {
      u= Dequeue(Q)
      for each v in G.AdjacencyList[u] {
          if (v.color is white) {
              v.color = grey
              v.d = u.d + 1
              v.phi = u
              Enqueue(Q, v)
              //Step++;
          }
      }
      u.color = black
      //Step++
  }
}