day 21

1 files changed, 26 insertions, 0 deletions

diff --git a/AoC2022/21/solver.lisp b/AoC2022/21/solver.lisp
new file mode 100644
index 0000000..fa28e31
--- /dev/null
+++ b/AoC2022/21/solver.lisp
@@ -0,0 +1,26 @@
+(ql:quickload '(fiveam uiop cl-ppcre trivia))
+
+(defun build-monkey-table (filename)
+  (let ((table (make-hash-table :test #'eq)))
+    (with-open-file (stream filename)
+      (loop for line = (read-line stream nil nil)
+            while line
+            do
+               (cond
+                 ((ppcre:register-groups-bind ((#'read-from-string monkey dep1 op dep2))
+                      ("(\\w+): (\\w+) ([*+/-]) (\\w+)" line)
+                    (setf (gethash monkey table) (list op dep1 dep2))))
+                 ((ppcre:register-groups-bind ((#'read-from-string monkey number))
+                      ("(\\w+): (\\d+)" line)
+                    (setf (gethash monkey table) number))))))
+    table))
+
+(defun resolver (entry table)
+  (trivia:match entry
+    ((list op a b) (funcall op
+                            (resolver (gethash a table) table)
+                            (resolver (gethash b table) table)))
+    (a a)))
+
+(let ((table (build-monkey-table "input")))
+  (= 56490240862410 (resolver (gethash 'root table) table)))