From afe994a44396c3a8e5ad29ccc3d7f21e85fecd14 Mon Sep 17 00:00:00 2001
From: Oscar Najera <hi@oscarnajera.com>
Date: Sun, 4 Dec 2022 22:50:54 +0100
Subject: [AoC2022] Common Lisp 03

---
 AoC2022/03/makefile    |  2 +-
 AoC2022/03/solver.lisp | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 AoC2022/03/solver.lisp

diff --git a/AoC2022/03/makefile b/AoC2022/03/makefile
index f781686..630e630 100644
--- a/AoC2022/03/makefile
+++ b/AoC2022/03/makefile
@@ -10,5 +10,5 @@
 
 run:
 	emacs -batch -l ert -l solver.el -f ert-run-tests-batch-and-exit
-	# sbcl --load ~/.sbclrc --script solver.lisp
+	sbcl --load ~/.sbclrc --script solver.lisp
 	rustc solver.rs && ./solver
diff --git a/AoC2022/03/solver.lisp b/AoC2022/03/solver.lisp
new file mode 100644
index 0000000..a221495
--- /dev/null
+++ b/AoC2022/03/solver.lisp
@@ -0,0 +1,55 @@
+(ql:quickload :fiveam)
+
+(defun recover-item (bitfield-int)
+  (loop for i from 0
+        when (logbitp i bitfield-int) return i))
+
+(defun priority (value)
+  (if (< value 31) ;; It is a capital letter in range [1;26]
+      (+ value 26)
+    (- value 32)))
+
+(defun line-priority (str)
+  (let ((mid (/ (length str) 2))
+        (left-pack 0) (right-pack 0))
+    (loop with cross = 0
+          for l across (subseq str 0 mid)
+          for r across (subseq str mid)
+          do (progn
+               (setf left-pack (logior left-pack (ash 1 (- (char-code l) 64))))
+               (setf right-pack (logior right-pack (ash 1 (- (char-code r) 64))))
+               (setf cross (logand left-pack right-pack)))
+          when (< 0 cross) return (priority (recover-item cross)))))
+
+
+(defun prio ()
+  (with-open-file (in "input")
+    (loop :for l = (read-line in nil nil)
+          :while l
+          :sum (line-priority l))))
+
+(defun pick-badge (str)
+  (loop with stack = 0
+        for i across str
+        do (setf stack (logior stack (ash 1 (- (char-code i) 64))))
+        finally (return stack)))
+
+(defun badge ()
+  (with-open-file (in "input")
+    (loop :for b = (loop repeat 3 for l = (read-line in nil nil) while l collect (pick-badge l))
+          :while b
+          :sum (priority (recover-item (apply #'logand b))))))
+
+;; (pick-badge "LdHVLDLDdHdtLMhcqCqGWcWg" )
+
+(fiveam:test intermediate
+             (fiveam:is (= 12 (recover-item 4096)))
+             (fiveam:is (= 20 (line-priority
+                               "gzCjffWZCtCfZZVdqVSqJdvJndSt"))))
+
+(fiveam:test results
+  (fiveam:is (= 8072 (prio)))
+  (fiveam:is (= 2567 (badge))))
+
+
+(fiveam:run-all-tests)
-- 
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