Maze generation
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Generate and show a maze, using using the simple Depth-first search algorithm.
J
This algorithm allows almost no parallelism. So, while it might be "simple", it will not be necessarily efficient to implement on future (highly parallel) systems.
Anyways, based on the picolisp implementation, except without any relevant grid support:
<lang j>maze=:4 :0
horiz=. 0$~x,y-1 verti=. 0$~(x-1),y unvisited=. 0,0,~|:0,0,~1$~y,x path=.,:here=. ?x,y while.1 e.,unvisited do. unvisited=.0 (<here+1)} unvisited neighbors=. here+"1 (,-)=0 1 neighbors=. neighbors #~ (<"1 neighbors+1) {unvisited if.#neighbors do. next=. ({~ ?@#) neighbors if.{.next=here do. horiz=.1 (<-:here+next-0 1)} horiz else.verti=. 1 (<-:here+next-1 0)} verti end. path=.path,here=.next else. here=.{:path path=.}:path end. end. horiz;verti
)
display=:3 :0
size=. >.&$&>/y text=. (}:1 3$~2*1+{:size)#"1":size$<' ' 'hdoor vdoor'=. 2 4&*&.>&.> (#&,{@;&i./@$)&.> y ' ' (a:-.~0 1;0 2; 0 3;(2 1-~$text);(1 4&+&.> hdoor),,vdoor+&.>"0/2 1;2 2;2 3)} text
)</lang>
Example use (with ascii box drawing enabled):
<lang j> display 12 maze 16 + +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | | | | + +---+---+---+---+ + + +---+---+ +---+ +---+---+ + | | | | | | | | | +---+---+ + +---+---+ + + +---+---+ +---+---+ + + | | | | | | | | | + +---+ +---+---+ + + + + +---+---+ + +---+ + | | | | | | | | | | + +---+---+---+ + +---+---+ + + + +---+---+---+---+ | | | | | | | | | | + + + +---+---+ +---+ +---+ + +---+---+---+ + + | | | | | | | + + +---+---+---+---+---+---+ +---+---+ + +---+---+ + | | | | | | | | | + +---+---+---+---+ + + + + + + + + +---+---+ | | | | | | | | | | + + +---+ + + + +---+---+ +---+---+---+---+ +---+ | | | | | | | | | + + + +---+ +---+ + +---+ +---+---+---+---+---+ + | | | | | | | | | | + +---+ + + + +---+ +---+---+ +---+ + + +---+ | | | | | | | | | | | | +---+ + + + + +---+---+ + +---+ +---+---+---+ + | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+</lang>
PicoLisp
This solution uses 'grid' from "lib/simul.l" to generate the two-dimensional structure. <lang PicoLisp>(load "@lib/simul.l")
(de maze (DX DY)
(let Maze (grid DX DY) (let Fld (get Maze (rand 1 DX) (rand 1 DY)) (recur (Fld) (for Dir (shuffle '((west . east) (east . west) (south . north) (north . south))) (with ((car Dir) Fld) (unless (or (: west) (: east) (: south) (: north)) (put Fld (car Dir) This) (put This (cdr Dir) Fld) (recurse This) ) ) ) ) ) (for (X . Col) Maze (for (Y . This) Col (set This (cons (cons (: west) (or (: east) (and (= Y 1) (= X DX)) ) ) (cons (: south) (or (: north) (and (= X 1) (= Y DY)) ) ) ) ) (=: west) (=: east) (=: south) (=: north) ) ) Maze ) )
(de display (Maze)
(disp Maze 0 '((This) " ")) )</lang>
Output:
: (display (maze 16 12)) + +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 12 | | | | | | + + + + + +---+ + +---+---+ + +---+ +---+ + 11 | | | | | | | | | | | + +---+ +---+---+ +---+---+ + +---+---+ +---+ +---+ 10 | | | | | | | | | | + + + +---+ + + + + +---+---+ +---+ +---+ + 9 | | | | | | | | | | | + +---+---+ + +---+ +---+---+ + + + +---+ + + 8 | | | | | | | | | | + + + + + +---+---+ +---+ +---+---+ +---+ + + 7 | | | | | | | | | | +---+ +---+---+---+---+ +---+ +---+ + +---+ +---+ + 6 | | | | | | | | | | | + +---+ +---+ +---+ + +---+ + +---+---+---+ + + 5 | | | | | | | | +---+ +---+ +---+ +---+ +---+---+ + +---+ +---+ + 4 | | | | | | | | | | | + +---+ +---+ +---+ +---+ + + +---+---+ + +---+ 3 | | | | | | | | | | + +---+---+ + + +---+---+---+ +---+ + + +---+ + 2 | | | | | | | | | | + + + +---+ + + +---+ +---+ +---+ + +---+---+ 1 | | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ a b c d e f g h i j k l m n o p