Maze Generator

import random

WIDTH = 39  # Width of the maze (must be odd).
HEIGHT = 19  # Height of the maze (must be odd).
SEED = 1
random.seed(SEED)
assert WIDTH % 2 == 1 and WIDTH > 2
assert HEIGHT % 2 == 1 and HEIGHT > 2

# Use these characters for displaying the maze:
EMPTY = ' '
MARK = '@'
WALL = chr(9608)  # Character 9608 is '█'
NORTH, SOUTH, EAST, WEST = 'n', 's', 'e', 'w'

def displayMaze(maze, markX=None, markY=None):
    """Displays the maze data structure in the maze argument. The
    markX and markY arguments are coordinates of the current
    '@' location of the algorithm as it generates the maze."""
    for y in range(HEIGHT):
        for x in range(WIDTH):
            if markX == x and markY == y:
                # Display the '@' mark here:
                print(MARK, end='')
            else:
                # Display the wall or empty space:
                print(maze[(x, y)], end='')
        print()  # Print a newline after printing the row.

def visit(x, y):
    """"Carve out" empty spaces in the maze at x, y and then
    recursively move to neighboring unvisited spaces. This
    function backtracks when the mark has reached a dead end."""
    global hasVisited, maze

    maze[(x, y)] = EMPTY  # "Carve out" the space at x, y.
    displayMaze(maze, x, y)  # Display the maze as we generate it.
    print('\n\n')

    while True:
        # Check which neighboring spaces adjacent to
        # the mark have not been visited already:
        unvisitedNeighbors = []
        if y > 1 and (x, y - 2) not in hasVisited:
            unvisitedNeighbors.append(NORTH)
        if y < HEIGHT - 2 and (x, y + 2) not in hasVisited:
            unvisitedNeighbors.append(SOUTH)
        if x > 1 and (x - 2, y) not in hasVisited:
            unvisitedNeighbors.append(WEST)
        if x < WIDTH - 2 and (x + 2, y) not in hasVisited:
            unvisitedNeighbors.append(EAST)

        if len(unvisitedNeighbors) == 0:
            # BASE CASE
            # All neighboring spaces have been visited, so this is a
            # dead end. Backtrack to an earlier space:
            return
        else:
            # RECURSIVE CASE
            # Randomly pick an unvisited neighbor to visit:
            nextIntersection = random.choice(unvisitedNeighbors)

            # Move the mark to an unvisited neighboring space:
            if nextIntersection == NORTH:
                nextX = x
                nextY = y - 2
                maze[(x, y - 1)] = EMPTY  # Connecting hallway.
            elif nextIntersection == SOUTH:
                nextX = x
                nextY = y + 2
                maze[(x, y + 1)] = EMPTY  # Connecting hallway.
            elif nextIntersection == WEST:
                nextX = x - 2
                nextY = y
                maze[(x - 1, y)] = EMPTY  # Connecting hallway.
            elif nextIntersection == EAST:
                nextX = x + 2
                nextY = y
                maze[(x + 1, y)] = EMPTY  # Connecting hallway.

            hasVisited.append((nextX, nextY))  # Mark as visited.
            visit(nextX, nextY)  # Recursively visit this space.


# Create the filled-in maze data structure to start:
maze = {}
for x in range(WIDTH):
    for y in range(HEIGHT):
        maze[(x, y)] = WALL  # Every space is a wall at first.

# Carve out the paths in the maze data structure:
hasVisited = [(1, 1)]  # Start by visiting the top left corner.
visit(1, 1)

# Display the final resulting maze data structure:
displayMaze(maze)