1 files changed, 60 insertions, 0 deletions
diff --git a/AoC2023/day19/solver.lisp b/AoC2023/day19/solver.lisp
new file mode 100644
index 0000000..9c2f0a0
--- /dev/null
+++ b/AoC2023/day19/solver.lisp
@@ -0,0 +1,60 @@
+;;6:51
+;;7:49
+;;
+(ql:quickload '(fiveam cl-ppcre arrows))
+
+(defstruct part
+  x m a s)
+
+(defun part-sum (part)
+  (with-slots (x m a s) part
+    (+ x m a s)))
+
+(defun solve (filename)
+  (let ((workflows (make-hash-table))
+        parts)
+    (loop for line in (uiop:read-file-lines filename)
+          do
+             (cond
+               ((string-equal line ""))
+               ((eq #\{ (aref line 0))
+                (cl-ppcre:register-groups-bind ((#'parse-integer x m a s))
+                    ("{x=\(\\d+\),m=\(\\d+\),a=\(\\d+\),s=\(\\d+\)}" line)
+                  (push (make-part :x x :m m :a a :s s) parts)))
+               ((multiple-value-bind (name rule) (parse-rule line)
+                  (setf (gethash name workflows) rule)))))
+    (reduce #'+  parts :key (alexandria:curry #'test-part workflows))))
+
+(defun parse-tests (line-rule)
+  (loop for test in (cl-ppcre:split "," line-rule)
+        collect
+        (cl-ppcre:register-groups-bind ((#'read-from-string prop op val target))
+            ("\(\\w\)\(<|>\)\(\\d+\):\(\\w+\)" test)
+          (list op prop val target))))
+
+(fiveam:test parts
+  (fiveam:is (equal
+              '((< S 537 GD) (> X 2440 R))
+              (parse-tests "s<537:gd,x>2440:R" ))))
+
+(fiveam:test solutions
+  (fiveam:is (= 19114 (solve "eg-in")))
+  (fiveam:is (= 446517 (solve "input"))))
+
+(defun parse-rule (line)
+  (cl-ppcre:register-groups-bind ((#'read-from-string name) (#'parse-tests tests) (#'read-from-string default))
+      ("\(\\w+\){\(.*\),\(\\w+\)}" line)
+    (values name
+            (lambda (part)
+              (or (loop for (op prop val target) in tests
+                        when (funcall op (slot-value part prop) val)
+                          do (return target))
+                  default)))))
+
+(defun test-part (workflows part &optional (start 'in))
+  (let ((out (funcall (gethash start workflows) part)))
+    (cond ((eq 'A out)
+           (part-sum part))
+          ((eq 'R out) 0)
+          ((test-part workflows part out)))))
+(fiveam:run!)