Add day03 - 2024HEADmaster

2 files changed, 56 insertions, 0 deletions

diff --git a/2024/aoc-utils.scm b/2024/aoc-utils.scm
index 98e83cd..5deb269 100644
--- a/2024/aoc-utils.scm
+++ b/2024/aoc-utils.scm
@@ -4,6 +4,7 @@
   #:use-module (ice-9 regex)
   #:use-module (ice-9 rdelim)
   #:export (file->list
+            file->str
             lines->number-list))
 
 (define (file->list filename)
@@ -11,6 +12,9 @@
     ; Remove EOF token
     (take lines (1- (length lines)))))
 
+(define (file->str filename)
+  (call-with-input-file filename read-string))
+
 (define (lines->number-list lines)
   (map (lambda (line)
          (map string->number (string-split line #\Space)))
diff --git a/2024/day03/main.scm b/2024/day03/main.scm
new file mode 100755
index 0000000..1a8505d
--- /dev/null
+++ b/2024/day03/main.scm
@@ -0,0 +1,52 @@
+#!/usr/bin/guile -s
+!#
+
+(add-to-load-path (format #f "~a/2024" (getcwd)))
+(add-to-load-path (format #f "~a/.." (dirname (current-filename))))
+
+(use-modules
+ (aoc-utils)
+ (srfi srfi-1)
+ (srfi srfi-9)
+ (ice-9 regex))
+
+(define mul-rx (make-regexp "mul\\(([0-9]+),([0-9]+)\\)"))
+
+(define (mul str)
+  (let ((match (regexp-exec mul-rx str)))
+    (* (string->number (match:substring match 1))
+       (string->number (match:substring match 2)))))
+
+(define (not-corrupted-mults memory)
+  (map match:substring (list-matches mul-rx memory)))
+
+(define (part1 memory)
+  (apply + (map mul (not-corrupted-mults memory))))
+
+(define or-rx (make-regexp "do\\(\\)|don't\\(\\)|mul\\([0-9]+,[0-9]+\\)"))
+
+(define (part2 memory)
+  (let ((tokens (map match:substring (list-matches or-rx memory)))
+        (enabled? #t))
+    (apply + (map (lambda (match)
+                    (cond ((string= "do()" match) (begin
+                                                    (set! enabled? #t)
+                                                    0))
+                          ((string= "don't()" match) (begin
+                                                       (set! enabled? #f)
+                                                       0))
+                          (else (if enabled?
+                                    (mul match)
+                                    0))))
+                  tokens))))
+
+(define (main)
+  (let ((memory (file->str "input.txt")))
+    (display "Part1: ")
+    (display (part1 memory))
+    (newline)
+    (display "Part2: ")
+    (display (part2 memory))
+    (newline)))
+
+(main)