From 1daa7758cc4eba6d353282042bbfd0efc2074dc4 Mon Sep 17 00:00:00 2001
From: haskal <haskal@awoo.systems>
Date: Tue, 8 Dec 2020 00:17:32 -0500
Subject: [PATCH] jesus christ i am legit ashamed that i wrote this

---
 8.rkt | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 8.rkt

diff --git a/8.rkt b/8.rkt
new file mode 100644
index 0000000..e320ee8
--- /dev/null
+++ b/8.rkt
@@ -0,0 +1,66 @@
+#lang curly-fn racket
+
+(require "scripts/aoc.rkt")
+
+;; solution for day 8
+
+(struct insn [type arg] #:transparent)
+
+;; helper functions here
+
+(define (part1 input)
+  (define (execute pc acc [seen (mutable-set)])
+    (if (set-member? seen pc)
+      acc
+      (let ([in (list-ref input pc)])
+        (set-add! seen pc)
+        (match (insn-type in)
+          ["nop" (execute (add1 pc) acc seen)]
+          ["jmp" (execute (+ pc (insn-arg in)) acc seen)]
+          ["acc" (execute (add1 pc) (+ acc (insn-arg in)) seen)]
+          [x (error "not shonks" x)]))))
+  (execute 0 0))
+
+(define (part2 input)
+  (define (execute-actual input)
+    (define (execute pc acc [seen (mutable-set)])
+      (if (>= pc (length input))
+        acc
+        (let ([in (list-ref input pc)])
+          (set-add! seen pc)
+          (match (insn-type in)
+            ["nop" (execute (add1 pc) acc seen)]
+            ["jmp" (execute (+ pc (insn-arg in)) acc seen)]
+            ["acc" (execute (add1 pc) (+ acc (insn-arg in)) seen)]
+            [x (error "not shonks" x)]))))
+    (execute 0 0))
+
+  (define target-pc (length input))
+  (for ([in (in-list input)] [i (in-naturals)] #:unless (string=? "acc" (insn-type in)))
+    (define new-type (if (string=? (insn-type in) "jmp") "nop" "jmp"))
+    (define new-insn (insn new-type (insn-arg in)))
+    ;; aaaa
+    (define vec (vector-copy (list->vector input)))
+    (vector-set! vec i new-insn)
+    (define new-prg (vector->list vec))
+    (with-handlers ([exn? (lambda (x) (answer 8 2 (execute-actual new-prg)))])
+      (part1 new-prg))))
+
+(module+ test
+  (require rackunit)
+  ;; tests here
+  (displayln "no tests :("))
+
+(module+ main
+  (define input
+    (for/list ([line (in-list (file->lines "inputs/8"))])
+      (match (string-split line)
+        [(list a b) (insn a (string->number b))]
+        [x (error "not shonks" x)])))
+  ;; part 1
+  (answer 8 1 (part1 input))
+
+  ;; part 2
+  (answer 8 2 (part2 input))
+
+  (displayln "meow"))