Pentomino tiling: Difference between revisions
→{{header|Racket}}
Line 1,044:
LLLLNNWI
</pre>
=={{header|Racket}}==
{{trans|Java}}
(although purely functional, so no need to undo the tiling attempts)
<lang racket>#lang racket
(require racket/hash)
(module+ main (Pentomino-tiling))
(define n-rows 8)
(define n-cols 8)
(define blank '-)
(define (build-grid)
(for/fold ((grid (for*/hash ((r n-rows) (c n-cols)) (values (cons r c) #f)))) ((_ 4))
(hash-set grid (cons (random n-rows) (random n-cols)) blank)))
(define (make-shapes-map)
(hash 'F (F) 'I (I) 'L (L) 'N (N) 'P (P) 'T (T) 'U (U) 'V (V) 'W (W) 'X (X) 'Y (Y) 'Z (Z)))
(define (print-grid grid)
(for ((r n-rows) #:when (when (positive? r) (newline)) (c n-cols))
(write (hash-ref grid (cons r c))))
(newline))
(define (Pentomino-tiling (grid (build-grid)))
(define solution (solve 0 grid (make-shapes-map)))
(if solution (print-grid solution) (displayln "no solution")))
(define (solve p grid shapes (failed-shapes (hash)))
(define-values (r c) (quotient/remainder p n-cols))
(cond [(not grid) #f]
[(hash-empty? shapes) (and (hash-empty? failed-shapes) grid)]
[(hash-ref grid (cons r c) #f) (solve (add1 p) grid shapes failed-shapes)]
[else
(define s (car (hash-keys shapes)))
(define os (hash-ref shapes s))
(define shapes-s (hash-remove shapes s))
(define (try-place-orientation o)
(and (for/and ((dy.dx o))
(let ((y (+ r (car dy.dx))) (x (+ c (cdr dy.dx))))
(and (>= x 0) (>= y 0) (< x n-cols) (< y n-rows) (not (hash-ref grid (cons y x))))))
(for/fold ((grid (hash-set grid (cons r c) s))) ((dy.dx o))
(hash-set grid (cons (+ r (car dy.dx)) (+ c (cdr dy.dx))) s))))
(or (for*/first
((o os)
(solution (in-value (solve (add1 p)
(try-place-orientation o)
(hash-union shapes-s failed-shapes))))
#:when solution)
solution)
(solve p grid shapes-s (hash-set failed-shapes s os)))]))
(define (F) '(((1 . -1) (1 . 0) (1 . 1) (2 . 1))
((0 . 1) (1 . -1) (1 . 0) (2 . 0))
((1 . 0) (1 . 1) (1 . 2) (2 . 1))
((1 . 0) (1 . 1) (2 . -1) (2 . 0))
((1 . -2) (1 . -1) (1 . 0) (2 . -1))
((0 . 1) (1 . 1) (1 . 2) (2 . 1))
((1 . -1) (1 . 0) (1 . 1) (2 . -1))
((1 . -1) (1 . 0) (2 . 0) (2 . 1))))
(define (I) '(((0 . 1) (0 . 2) (0 . 3) (0 . 4))
((1 . 0) (2 . 0) (3 . 0) (4 . 0))))
(define (L) '(((1 . 0) (1 . 1) (1 . 2) (1 . 3))
((1 . 0) (2 . 0) (3 . -1) (3 . 0))
((0 . 1) (0 . 2) (0 . 3) (1 . 3))
((0 . 1) (1 . 0) (2 . 0) (3 . 0))
((0 . 1) (1 . 1) (2 . 1) (3 . 1))
((0 . 1) (0 . 2) (0 . 3) (1 . 0))
((1 . 0) (2 . 0) (3 . 0) (3 . 1))
((1 . -3) (1 . -2) (1 . -1) (1 . 0))))
(define (N) '(((0 . 1) (1 . -2) (1 . -1) (1 . 0))
((1 . 0) (1 . 1) (2 . 1) (3 . 1))
((0 . 1) (0 . 2) (1 . -1) (1 . 0))
((1 . 0) (2 . 0) (2 . 1) (3 . 1))
((0 . 1) (1 . 1) (1 . 2) (1 . 3))
((1 . 0) (2 . -1) (2 . 0) (3 . -1))
((0 . 1) (0 . 2) (1 . 2) (1 . 3))
((1 . -1) (1 . 0) (2 . -1) (3 . -1))))
(define (P) '(((0 . 1) (1 . 0) (1 . 1) (2 . 1))
((0 . 1) (0 . 2) (1 . 0) (1 . 1))
((1 . 0) (1 . 1) (2 . 0) (2 . 1))
((0 . 1) (1 . -1) (1 . 0) (1 . 1))
((0 . 1) (1 . 0) (1 . 1) (1 . 2))
((1 . -1) (1 . 0) (2 . -1) (2 . 0))
((0 . 1) (0 . 2) (1 . 1) (1 . 2))
((0 . 1) (1 . 0) (1 . 1) (2 . 0))))
(define (T) '(((0 . 1) (0 . 2) (1 . 1) (2 . 1))
((1 . -2) (1 . -1) (1 . 0) (2 . 0))
((1 . 0) (2 . -1) (2 . 0) (2 . 1))
((1 . 0) (1 . 1) (1 . 2) (2 . 0))))
(define (U) '(((0 . 1) (0 . 2) (1 . 0) (1 . 2))
((0 . 1) (1 . 1) (2 . 0) (2 . 1))
((0 . 2) (1 . 0) (1 . 1) (1 . 2))
((0 . 1) (1 . 0) (2 . 0) (2 . 1))))
(define (V) '(((1 . 0) (2 . 0) (2 . 1) (2 . 2))
((0 . 1) (0 . 2) (1 . 0) (2 . 0))
((1 . 0) (2 . -2) (2 . -1) (2 . 0))
((0 . 1) (0 . 2) (1 . 2) (2 . 2))))
(define (W) '(((1 . 0) (1 . 1) (2 . 1) (2 . 2))
((1 . -1) (1 . 0) (2 . -2) (2 . -1))
((0 . 1) (1 . 1) (1 . 2) (2 . 2))
((0 . 1) (1 . -1) (1 . 0) (2 . -1))))
(define (X) '(((1 . -1) (1 . 0) (1 . 1) (2 . 0))))
(define (Y) '(((1 . -2) (1 . -1) (1 . 0) (1 . 1))
((1 . -1) (1 . 0) (2 . 0) (3 . 0))
((0 . 1) (0 . 2) (0 . 3) (1 . 1))
((1 . 0) (2 . 0) (2 . 1) (3 . 0))
((0 . 1) (0 . 2) (0 . 3) (1 . 2))
((1 . 0) (1 . 1) (2 . 0) (3 . 0))
((1 . -1) (1 . 0) (1 . 1) (1 . 2))
((1 . 0) (2 . -1) (2 . 0) (3 . 0))))
(define (Z) '(((0 . 1) (1 . 0) (2 . -1) (2 . 0))
((1 . 0) (1 . 1) (1 . 2) (2 . 2))
((0 . 1) (1 . 1) (2 . 1) (2 . 2))
((1 . -2) (1 . -1) (1 . 0) (2 . -2))))
</lang>
{{out}}
<pre>-UUUPPPI
NUXUPPTI
NXXXTTTI
NNXVVVTI
-NZ-WVFI
ZZZWWVFF
ZYWWLFF-
YYYYLLLL</pre>
=={{header|Visual Basic .NET}}==
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