Kazinator's Advent of Code stuff.

1 files changed, 49 insertions, 0 deletions

diff --git a/2021/12/one.tl b/2021/12/one.tl
new file mode 100644
index 0000000..70e36d5
--- /dev/null
+++ b/2021/12/one.tl
@@ -0,0 +1,49 @@
+(defvar %cave-hash% (hash))
+
+(defstruct cave ()
+  name
+  neighbors
+
+  (:postinit (cv)
+    (assert cv.name)
+    (set [%cave-hash% cv.name] cv)))
+
+(defstruct small-cave cave
+  (:method visit (cv path fn)
+    (unless (member cv path)
+      (push cv path)
+      (each ((n cv.neighbors))
+        n.(visit path fn)))))
+
+(defstruct big-cave cave
+  (:method visit (cv path fn)
+    (push cv path)
+    (each ((n cv.neighbors))
+      n.(visit path fn))))
+
+(defstruct end-cave cave
+  (:method visit (cv path fn)
+    (push cv path)
+    [fn path]))
+
+(defun ensure-cave (name)
+  (or [%cave-hash% name]
+      (set [%cave-hash% name]
+           (match-case name
+             ("end" (new end-cave name name))
+             (@[all @str chr-islower] (new small-cave name name))
+             (@else (new big-cave name name))))))
+
+(defun read-caves (: (name "input"))
+  (with-stream (s (open-file name))
+    (whilet ((line (get-line s)))
+      (match `@a-@b` line
+        (let ((ca (ensure-cave a))
+              (cb (ensure-cave b)))
+          (pushnew cb ca.neighbors)
+          (pushnew ca cb.neighbors))))))
+
+(defun find-paths (fn)
+  (let ((start [%cave-hash% "start"]))
+    (assert start)
+    start.(visit nil fn)))