day02.scm - advent-of-code - Perserverance, or the lack thereof

day02.scm (1974B)

    1 (use-modules (ice-9 popen))
    2 (use-modules (ice-9 rdelim))
    3 (use-modules (ice-9 format))
    4 (use-modules (ice-9 regex))
    5 (use-modules (srfi srfi-1))
    6 
    7 (define (extract-set-count set)
    8   (let ((r (string-match " ([0-9]+) red" set))
    9         (g (string-match " ([0-9]+) green" set))
   10         (b (string-match " ([0-9]+) blue" set)))
   11     (list (if r (string->number (regexp-substitute #f r 1)) 0)
   12           (if g (string->number (regexp-substitute #f g 1)) 0)
   13           (if b (string->number (regexp-substitute #f b 1)) 0))))
   14 
   15 (define (is-set-possible set bag)
   16   (reduce (lambda (a b) (and a b)) #t (map <= set bag)))
   17 
   18 (define (is-game-possible game bag)
   19   (let* ((tmp (string-split game #\:))
   20          (game-id (string->number
   21                    (regexp-substitute #f (string-match "Game ([0-9]+)" (car tmp)) 1)))
   22          (game-possible (fold (lambda (set res)
   23                                 (and res (is-set-possible (extract-set-count set) bag)))
   24                               #t
   25                               (string-split (car (cdr tmp)) #\;))))
   26     (if game-possible game-id 0)))
   27 
   28 (let ((file (open-input-file "input.txt")) (tot 0))
   29   (while #t
   30          (let ((line (car (%read-line file))))
   31            (if (eof-object? line)
   32                (break)
   33                (set! tot (+ tot (is-game-possible line '(12 13 14)))))))
   34   ;; 2085
   35   (format #t "Part 1: ~d" tot)
   36   (newline))
   37 
   38 (define (get-game-power game)
   39   (let* ((set-counts (map extract-set-count
   40                           (string-split (car (cdr (string-split game #\:))) #\;)))
   41          (min-bag (fold (lambda (next curr) (map max next curr))
   42                         '(0 0 0)
   43                         set-counts)))
   44     (reduce * 1 min-bag)))
   45 
   46 (let ((file (open-input-file "input.txt")) (tot 0))
   47   (while #t
   48          (let ((line (car (%read-line file))))
   49            (if (eof-object? line)
   50                (break)
   51                (set! tot (+ tot (get-game-power line))))))
   52   ;; 79315
   53   (format #t "Part 2: ~d" tot)
   54   (newline))