def breadthFirstSearch(problem):
"""
Search the shallowest nodes in the search tree first.
[2nd Edition: p 73, 3rd Edition: p 82]
"""
"*** YOUR CODE HERE ***"
from game import Directions
from util import Queue
Explored = {}
Frontier = Queue()
node = 0
current = problem.getStartState()
#print "bfs first state", current
succ = problem.getSuccessors(current)
for k in succ:
#print "initial push",k
Frontier.push([k]);
while not (Frontier.isEmpty()):
current = Frontier.pop()
node = current[-1][0]
#print "curr path and node",current,node,"explored status",(node in Explored),"\n"
# check if done
if (problem.isGoalState(node)):
break
Explored[node] = 1;
if (len(Explored)%100) == 0:
print "ex",len(Explored)
#print node
#Explored[node[0]] = 1;
succ = problem.getSuccessors(node)
for k in succ:
if not (k[0] in Explored):
if not (Frontier.isPresent(current + [k])):
Frontier.push(current + [k]);
sol = []
for k in current:
sol += [k[1]]
#print current
#print "action sol", sol
return sol
