From 6034110b9ffdadde83dc57f14e8d24a94b6587ff Mon Sep 17 00:00:00 2001
From: Oscar Najera <hi@oscarnajera.com>
Date: Thu, 7 Dec 2023 10:11:55 +0100
Subject: part2

---
 AoC2023/day07/solver.lisp | 73 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 52 insertions(+), 21 deletions(-)

diff --git a/AoC2023/day07/solver.lisp b/AoC2023/day07/solver.lisp
index 3a1fe8a..4cb0a9e 100644
--- a/AoC2023/day07/solver.lisp
+++ b/AoC2023/day07/solver.lisp
@@ -11,15 +11,23 @@ KK677 28
 KTJJT 220
 QQQJA 483")
 
-(defun occurences (str)
-  (let ((bag (make-hash-table)))
-    (loop
-      for le across str
-      do (incf (gethash le bag 0)))
-    (sort (alexandria:hash-table-values bag) #'>)))
+(defun occurences (str &optional joker)
+  (let* ((bag (make-hash-table))
+         (jokers
+           (loop
+             for le across str
+             do (incf (gethash le bag 0))
+             count (eq le #\J)))
+         (result (sort (alexandria:hash-table-values bag) #'>)))
+    (when joker
+      (setf result (remove jokers result :count 1))
+      (if (= jokers 5)
+          (setf result '(5))
+          (incf (car result) jokers)))
+    result))
 
-(defun hand-type (str)
-  (trivia:match (occurences str)
+(defun hand-type (str &optional joker)
+  (trivia:match (occurences str joker)
     ((list 5) 5)
     ((list 4 1) 4)
     ((list 3 2) 3)
@@ -28,27 +36,38 @@ QQQJA 483")
     ((list 2 1 1 1) 0)
     ((list 1 1 1 1 1) -1)))
 
-(defun card-strength (card)
-  (position card "23456789TJQKA"))
+(defun card-strength (card &optional joker)
+  (position card
+            (if joker
+                "J23456789TQKA"
+                "23456789TJQKA")))
 
-(defun card-< (a b)
-  (< (card-strength a) (card-strength b)))
+(defun card-< (a b &optional joker)
+  (< (card-strength a joker) (card-strength b joker)))
 
-(defun hand-< (a b)
-  (let ((a-t (hand-type a))
-        (b-t (hand-type b)))
+(defun hand-< (a b &optional joker)
+  (let ((a-t (hand-type a joker))
+        (b-t (hand-type b joker)))
     (cond
       ((< a-t b-t))
       ((= a-t b-t)
        (loop for l across a
              for s across b
              unless (eq l s)
-               return (card-< l s))))))
+               return (card-< l s joker))))))
 
 (f:test partial
   (f:is
    (equal '(3 1 1)
           (occurences "QJQAQ")))
+  (f:is
+   (equal '(4 1)
+          (occurences "QJQAQ" 'joker)))
+  (f:is
+   (equal '(5)
+          (occurences "JJJJJ" 'joker)))
+  (f:is (card-< #\2 #\J))
+  (f:is-false (card-< #\2 #\J 'joker))
   (f:is (hand-< "2AAAA" "33332"))
   (f:is (hand-< "77788" "77888"))
   (f:is (hand-< "77788" "77778")))
@@ -65,16 +84,28 @@ QQQJA 483")
         for c from 1
         sum (* c bid)))
 
-(defun solver1 (lines)
+(defun solver (lines &optional joker)
   (arrows:->
    (parse-input lines)
-   (sort #'hand-< :key #'car)
+   (sort (lambda (a b)
+           (hand-< a b joker))
+         :key #'car)
    (total-win)))
+
 (f:test solutions
   (f:is
    (= 6440
-      (solver1 eg-input)))
+      (solver eg-input)))
+  (f:is
+   (= 5905
+      (solver eg-input 'joker)))
   (f:is
    (= 253205868
-      (solver1
-       (uiop:read-file-string "input")))))
+      (solver
+       (uiop:read-file-string "input"))))
+  (f:is
+   (= 253907829
+      (solver
+       (uiop:read-file-string "input") 'joker))))
+
+;; part2
-- 
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