EightPuzzle.py

from search import *

eight_puzzle = EightPuzzle((1, 2, 3, 5, 7, 4, 8, 6, 0)) # <- change this

class EightPuzzle(Problem):

def __init__(self, initial, goal=(1, 2, 3, 4, 5, 6, 7, 8, 0)):
    super().__init__(initial, goal)
def goal_test(self, state):
    return state == self.goal

def find_blank_square(self, state):
    """Return the index of the blank square in a given state"""
    return state.index(0)


greedy_best_first_graph_search = best_first_graph_search

def astar_search(problem, h=None, display=False):
    h = memoize(h or problem.h, 'h')
    return best_first_graph_search(problem, lambda n: n.path_cost + h(n), display)


def actions(self, state):
    possible_actions = ['UP', 'DOWN', 'LEFT', 'RIGHT']
    index_blank_square = self.find_blank_square(state)

    if index_blank_square == 0:
        return ['DOWN','RIGHT']
    if index_blank_square == 1:
        return ['DOWN','LEFT','RIGHT']
    if index_blank_square == 2:
        return ['LEFT','DOWN']
    if index_blank_square == 3:
        return ['DOWN','RIGHT','UP']
    if index_blank_square == 4:
        return ['DOWN','RIGHT','UP','LEFT']
    if index_blank_square == 5:
        return ['DOWN','UP','LEFT']
    if index_blank_square == 6:
        return ['UP','RIGHT']
    if index_blank_square == 7:
        return ['LEFT','RIGHT','UP']
    if index_blank_square == 8:
        return ['UP','LEFT']

def result(self, state, action):
    """ Given state and action, return a new state that is the result of the action.
    Action is assumed to be a valid action in the state """

    # blank is the index of the blank square
    blank = self.find_blank_square(state)
    new_state = list(state)

    delta = {'UP': -3, 'DOWN': 3, 'LEFT': -1, 'RIGHT': 1}
    neighbor = blank + delta[action]
    new_state[blank], new_state[neighbor] = new_state[neighbor], new_state[blank]

    return tuple(new_state)

if name == 'main':
#solution = depth_first_graph_search(eight_puzzle).solution()
#print(solution)
#solution = breadth_first_graph_search(eight_puzzle).solution()
#print(solution)
print(breadth_first_graph_search(eight_puzzle, display=True).solution())
print(astar_search(eight_puzzle, h=None, display=True).solution())
#print(eight_puzzle.actions((0, 1, 2, 3, 4, 5, 6, 7, 8)))
#print(eight_puzzle.result((0, 1, 2, 3, 4, 5, 6, 7, 8), 'DOWN'))
#print(breadth_first_graph_search(eight_puzzle).solution())