foobar/bunniesescape4.py at master · jasonsross/foobar · GitHub

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# -*- coding: utf-8 -*-
"""
Created on Thu Aug 03 20:08:54 2017

@author: jasonros
"""

import pandas as pd

def answer(maze):
    from collections import deque

    def memodict(f):
        """ Memoization decorator for a function taking a single argument """
        class memodict(dict):

            def __missing__(self, key):
                ret = self[key] = f(key)
                return ret
        return memodict().__getitem__

    def adjacent_to((maze_dim, (i, j))):
        neighbors = (
            (i - 1, j),
            (i, j - 1),
            (i, j + 1),
            (i + 1, j))

        return [p for p in neighbors if 0 <= p[0] < maze_dim[0] and 0 <= p[1] < maze_dim[1]]

    def removable(maze, i, j):
        counter = 0
        for x, y in adjacent_to(((len(maze), len(maze[0])), (i, j))):
            if not maze[x][y]:
                if counter:
                    return True
                counter += 1
        return False


    if not maze:
        return 0

    dims = (len(maze), len(maze[0]))
    end_point = (dims[0]-1, dims[1]-1)

    # list of walls that can be removed
    passable_walls = set()
    for i in xrange(dims[0]):
        for j in xrange(dims[1]):
            if maze[i][j] == 1 and removable(maze, i, j):
                passable_walls.add((i, j))

    shortest_path = 0
    best_possible = dims[0] + dims[1] - 1

    path_mat = [[None] * dims[1] for _ in xrange(dims[0])]  # tracker matrix for shortest path
    path_mat[dims[0]-1][dims[1]-1] = 0  # set the starting point to destination (lower right corner)

    for wall in passable_walls:

        temp_maze = maze
        if wall:
            temp_maze[wall[0]][wall[1]] = 0

        stat_mat = [['-'] * dims[1] for _ in xrange(dims[0])]  # status of visited and non visited cells

        q = deque()
        q.append(end_point)

        while q:
            curr = q.popleft()

            if curr == (0,0):
                break

            for next in adjacent_to((dims, curr)):
                if temp_maze[next[0]][next[1]] == 0:  # Not a wall
                    temp = path_mat[curr[0]][curr[1]] + 1
                    if temp < path_mat[next[0]][next[1]] or path_mat[next[0]][next[1]] == None:  # there is a shorter path to this cell
                        path_mat[next[0]][next[1]] = temp
                    if stat_mat[next[0]][next[1]] != '+':  # Not visited yet
                        q.append(next)

            stat_mat[curr[0]][curr[1]] = '+'  # mark it as visited

        if path_mat[0][0]+1 <= best_possible:
            break

    if shortest_path == 0 or path_mat[0][0]+1 < shortest_path:
        shortest_path = path_mat[0][0]+1

    return shortest_path

maze = [
[0,1,1,0],
[0,0,0,1],
[1,1,0,0],
[1,1,1,0]
]
print answer(maze)
maze = [
[0, 0, 0, 0, 0, 0],
[1, 1, 1, 1, 1, 0],
[0, 0, 0, 0, 0, 0],
[0, 1, 1, 1, 1, 1],
[0, 1, 1, 1, 1, 1],
[0, 0, 0, 0, 0, 0]
]
print answer(maze)
maze = [
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
 ]

print answer(maze)
maze = [
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
 ]
print answer(maze)