add day 5 part 1 solution

1 files changed, 54 insertions, 0 deletions

diff --git a/5.scm b/5.scm
new file mode 100755
index 0000000..39929d3
--- /dev/null
+++ b/5.scm
@@ -0,0 +1,54 @@
+#!/usr/bin/env -S guile -s
+!#
+(use-modules (ice-9 regex)
+             (ice-9 textual-ports)
+             (srfi srfi-1))
+
+(define (read-lines port)
+  (letrec ((loop (lambda (l ls)
+                   (if (eof-object? l)
+                       ls
+                       (loop (get-line port) (cons l ls))))))
+    (reverse (loop (get-line port) '()))))
+
+(define (split-up nums)
+  (map string->number (filter (lambda (x) (not (string-null? x))) (string-split nums char-set:whitespace))))
+
+(define (perform-mapping val map)
+  (let* ((mapping (filter (lambda (x) (and (> val (cadr x))
+                                           (< val (+ (cadr x) (caddr x))))) map)))
+    (if (null? mapping) val
+        (+ val (- (caar mapping) (cadar mapping))))))
+
+(define (perform-all-mappings val maps)
+  (do ((i 0 (1+ i))) ((= i (length maps)))
+    (set! val (perform-mapping val (list-ref maps i))))
+  val)
+
+(define (parse-next-map lines)
+  (let ((map-started #f)
+        (map-parsed #f)
+        (current-map '()))
+    (while (not map-parsed)
+      (if (and (not map-started)
+               (string-match "map" (car lines)))
+          (set! map-started #t)
+          (when map-started
+            (if (string-match "[0-9]" (car lines))
+                (set! current-map (append current-map `(,(split-up (car lines)))))
+                (set! map-parsed #t))))
+      (set! lines (cdr lines)))
+    `(,current-map ,lines)))
+
+(let* ((port (open-input-file "5.txt"))
+       (lines (read-lines port))
+       (seeds (split-up (match:substring (string-match ": ([0-9| ]+)" (car lines)) 1)))
+       (lines (cdr lines))
+       (maps '()))
+  (close-port port)
+  (do ((i 0 (1+ i))) ((= i 7))
+    (let ((res (parse-next-map lines)))
+      (set! maps (append maps `(,(car res))))
+      (set! lines (cadr res))))
+  (let ((locations (map (lambda (x) (perform-all-mappings x maps)) seeds)))
+    (display (fold (lambda (x y) (if (> x y) y x)) (car locations) locations))))