Random maze generator using depth-first search.

It starts the maze path from a random cell and there is no exit defined but actually any 2 cells on the path (white cells) can be assigned to be entry and exit locations. (I could just add code to randomly select 2 white cells and change their colors to something else but I thought it looks better this way.)

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# Random Maze Generator using Depth-first Search
# http://en.wikipedia.org/wiki/Maze_generation_algorithm
# FB - 20121214
import random
from PIL import Image
imgx = 500; imgy = 500
image = Image.new("RGB", (imgx, imgy))
pixels = image.load()
mx = 50; my = 50 # width and height of the maze
maze = [[0 for x in range(mx)] for y in range(my)]
dx = [0, 1, 0, -1]; dy = [-1, 0, 1, 0] # 4 directions to move in the maze
color = [(0,0, 0), (255, 255, 255)] # RGB colors of the maze
# start the maze from a random cell
stack = [(random.randint(0, mx - 1), random.randint(0, my - 1))]
while len(stack) > 0:
(cx, cy) = stack[-1]
maze[cy][cx] = 1
# find a new cell to add
nlst = [] # list of available neighbors
for i in range(4):
nx = cx + dx[i]; ny = cy + dy[i]
if nx >= 0 and nx < mx and ny >= 0 and ny < my:
if maze[ny][nx] == 0:
# of occupied neighbors must be 1
ctr = 0
for j in range(4):
ex = nx + dx[j]; ey = ny + dy[j]
if ex >= 0 and ex < mx and ey >= 0 and ey < my:
if maze[ey][ex] == 1: ctr += 1
if ctr == 1: nlst.append(i)
# if 1 or more neighbors available then randomly select one and move
if len(nlst) > 0:
ir = nlst[random.randint(0, len(nlst) - 1)]
cx += dx[ir]; cy += dy[ir]
stack.append((cx, cy))
else: stack.pop()
# paint the maze
for ky in range(imgy):
for kx in range(imgx):
pixels[kx, ky] = color[maze[my * ky / imgy][mx * kx / imgx]]
image.save("Maze_" + str(mx) + "x" + str(my) + ".png", "PNG")
``` |

This would have been easier to read if you used more meaningful variable names. Looks good otherwise.

This is the recursive version (so it uses a stack implicitly instead of explicitly):

This version does not allow zigzag corridors, so the maze looks more conventional:

Why do you have to check every neighbor if it has only one visited neighbor? Can't we just choose a random neighbor x,y where maze[y][x]=0 , set maze[y][x] to 1 and add it the stack?