SearchAgent.py

from Node import Node
from Problem import Problem
import sys

def iterative_deepening_search(problem):
    for depth in range(sys.maxsize):
        result = depth_limited_search(problem, depth)
        if result != "cutoff":
            return result



def depth_limited_search(problem, limit = 200 ):
    def recursive_dls(node, problem, limit):
        if problem.goal_test(node.state):
            return node
        elif limit == 0:
            return "cutoff"
        else:
            cutoff = False
            for child in node.expand(problem):
                result = recursive_dls(child, problem, limit - 1)
                if result == "cutoff":
                    cutoff = True
                elif result is not None:
                    return result
            return "cutoff" if cutoff else None

    return recursive_dls(Node(problem.initial), problem, limit)