aoc

commit 00daf031374f5b3671df643f81d0506c5fc02278 (patch)
parent 8b19bd2b4aa8fbc54f7a34e766a9f5dfbee81323
Author: Alex Karle <alex@alexkarle.com>
Date:   Tue, 13 Dec 2022 23:21:54 -0500

day13: Add part 2

Diffstat:
M
2022/13/sol.scm
 | 
29
++++++++++++++++++++++++++---

1 file changed, 26 insertions(+), 3 deletions(-)
diff --git a/2022/13/sol.scm b/2022/13/sol.scm
@@ -2,6 +2,7 @@
 (import (chicken string)
         (chicken port)
         (chicken irregex)
+        (chicken sort)
         (chicken io))
 
 (define (parse line)
@@ -31,7 +32,7 @@
                     ((eq? g #t) #t)
                     (else "Bad result")))))))
 
-(define (parse-lines lines)
+(define (parse-pairs lines)
   (let loop ((lines lines))
     (if (null? lines)
         '()
@@ -39,6 +40,14 @@
               (right (parse (cadr lines))))  ; NOTE: not robust to bad input... (cdddr)
           (cons (list left right) (loop (cdddr lines)))))))
 
+(define (parse-all lines)
+  (let loop ((lines (append lines '("[[2]]" "[[6]]"))))
+    (if (null? lines)
+        '()
+        (if (equal? (car lines) "")
+            (loop (cdr lines))
+            (cons (parse (car lines)) (loop (cdr lines)))))))
+
 (define (score pairs)
   (let loop ((sum 0) (i 1) (ps pairs))
     (if (null? ps)
@@ -47,7 +56,21 @@
             (loop (+ i sum) (add1 i) (cdr ps))
             (loop sum (add1 i) (cdr ps))))))
 
+(define (index lst obj)
+  ;; why 1 indexed, advent of code??
+  (let loop ((i 1) (items lst))
+    (cond ((null? items) #f)
+          ((equal? (car items) obj) i)
+          (else (loop (add1 i) (cdr items))))))
+
+(define (signal all)
+  (let ((sorted (sort all (lambda (x y) (good? (list x y))))))
+    (* (index sorted '((2)))
+       (index sorted '((6))))))
+
 (define (main args)
   (let* ((lines (read-lines))
-         (pairs (parse-lines lines)))
-    (print (score pairs))))
+         (pairs (parse-pairs lines))
+         (all (parse-all lines)))
+    (print (score pairs))
+    (print (signal all))))