65 lines
1.8 KiB
Scheme
65 lines
1.8 KiB
Scheme
(load "../common.scm")
|
|
|
|
(define (read-starting-positions filename)
|
|
(call-with-input-file
|
|
filename
|
|
(lambda (file)
|
|
(let* [(player-1 (begin
|
|
(get-string-n file (string-length "Player 1 starting position: "))
|
|
(get-number file)))
|
|
(player-2 (begin
|
|
(get-string-n file (string-length "Player 2 starting position: "))
|
|
(get-number file)))]
|
|
; subtracting one to play with a board numbered 0..9 instead of 1..10, just easier
|
|
(values (- player-1 1) (- player-2 1))))))
|
|
|
|
(define (deterministic-dice)
|
|
(let [(value -1)]
|
|
(lambda ()
|
|
(set! value (mod (+ value 1) 100))
|
|
(+ value 1))))
|
|
|
|
(define (roll! position-score dice)
|
|
(set-car! position-score (mod (+ (car position-score) (dice) (dice) (dice)) 10))
|
|
(set-cdr! position-score (+ (car position-score) (cdr position-score) 1)))
|
|
|
|
(define (play-deterministic position-1 position-2)
|
|
(let [(player-1 (cons position-1 0))
|
|
(player-2 (cons position-2 0))
|
|
(dice (deterministic-dice))
|
|
(rolls 0)]
|
|
(let loop ()
|
|
(roll! player-1 dice)
|
|
(set! rolls (+ rolls 3))
|
|
(if (>= (cdr player-1) 1000)
|
|
(* (cdr player-2) rolls)
|
|
(begin
|
|
(roll! player-2 dice)
|
|
(set! rolls (+ rolls 3))
|
|
(if (>= (cdr player-1) 1000)
|
|
(* (cdr player-1) rolls)
|
|
(loop)))))))
|
|
|
|
(define (dirac-dice outcome)
|
|
(let [(next outcome)]
|
|
(lambda ()
|
|
(if (null? next)
|
|
#f
|
|
(let [(value (car next))]
|
|
(set! next (cdr next))
|
|
value)))))
|
|
|
|
(define (play-dirac position-1 position-2)
|
|
(let [(player-1 (list (cons position-1 0)))
|
|
(player-2 (list (cons position-2 0)))
|
|
(wins-1 0)
|
|
(wins-2 0)]
|
|
(let loop ()
|
|
'no-idea-yet)))
|
|
|
|
(let-values [((position-1 position-2) (read-starting-positions "input"))]
|
|
(printf "part 1:~% Rolls * Opponent Score = ~a~%"
|
|
(play-deterministic position-1 position-2))
|
|
(printf "part 2:~% Max Winning Universes: ~a~%"
|
|
(play-dirac position-1 position-2)))
|