day1 new regex trick

1 files changed, 13 insertions, 19 deletions

diff --git a/AoC2023/day01/solver.lisp b/AoC2023/day01/solver.lisp
index 2ab61e1..96f26f4 100644
--- a/AoC2023/day01/solver.lisp
+++ b/AoC2023/day01/solver.lisp
@@ -1,5 +1,4 @@
 (ql:quickload '(uiop fiveam cl-ppcre))
-
 (defvar eg-input "1abc2
 pqr3stu8vwx
 a1b2c3d4e5f
@@ -19,26 +18,22 @@ zoneight234
                          (find-if #'digit-char-p string)
                          (find-if #'digit-char-p string :from-end t)))))
 
+(defparameter numbers '(one two three four five six seven eight nine))
+(defparameter numbers-re (format nil "~{~(~a~)~^|~}" numbers))
+
 (defun translate (word)
-  (alexandria:eswitch (word :test (lambda (val opts) (member val opts :test #'string-equal)))
-    ('("1" "one") 1)
-    ('("2" "two") 2)
-    ('("3" "three") 3)
-    ('("4" "four") 4)
-    ('("5" "five") 5)
-    ('("6" "six") 6)
-    ('("7" "seven") 7)
-    ('("8" "eight") 8)
-    ('("9" "nine") 9)))
-
-(defparameter numbers-re "one|two|three|four|five|six|seven|eight|nine")
+  (or
+   (parse-integer word :junk-allowed t)
+   (1+ (position word numbers :test #'string-equal))))
 
 (defun line-value (string)
-  (let ((first (cl-ppcre:scan-to-strings (format nil "[1-9]|~a" numbers-re) string))
-        (last  (reverse (cl-ppcre:scan-to-strings (format nil "[1-9]|~a" (reverse numbers-re)) (reverse string)))))
-    (+ (* 10 (translate first)) (translate last))))
-
-(cl-ppcre:scan-to-strings (reverse numbers-re) (reverse "4nineeightseven2"))
+  (let (all)
+    (cl-ppcre:do-register-groups (m)
+        ((format nil "(?=([1-9]|~a))" numbers-re) string)
+      (push m all))
+    (setf all (nreverse all))
+    (+ (* 10 (translate (first all)))
+       (translate (car (last all))))))
 
 (defun solver1 (lines)
   (reduce #'+ lines :key #'get-pair))
@@ -60,4 +55,3 @@ zoneight234
   (fiveam:is
    (= 54925
       (solver2 (uiop:read-file-lines "input")))))
-