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-rw-r--r--AoC2022/13/solver.lisp42
1 files changed, 42 insertions, 0 deletions
diff --git a/AoC2022/13/solver.lisp b/AoC2022/13/solver.lisp
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+++ b/AoC2022/13/solver.lisp
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+(ql:quickload '(fiveam cl-json))
+
+(defun input (filename &optional dividers)
+ (with-open-file (in filename)
+ (let ((data (loop for a = (ignore-errors (list (json:decode-json in) (json:decode-json in)))
+ while a
+ nconc a)))
+ (if dividers (append '(((2)) ((6))) data) data))))
+
+(defun compare (f s)
+ (cond
+ ((eq f s) 'next)
+ ((and (null f) (not (null s))) t)
+ ((and (not (null f)) (null s)) nil)
+ ((and (integerp f) (integerp s)) (< f s))
+ ((and (integerp f) (consp s)) (compare (list f) s))
+ ((and (consp f) (integerp s)) (compare f (list s)))
+ ((let ((result (compare (car f) (car s))))
+ (if (eq 'next result) (compare (cdr f) (cdr s))
+ result)))))
+
+(defun solver-1 (filename)
+ (loop for i from 1
+ for (a b) on (input filename) by #'cddr
+ when (compare a b)
+ sum i))
+
+(fiveam:test first
+ (fiveam:is (= 13 (solver-1 "eg-in")))
+ (fiveam:is (= 5330 (solver-1 "input"))))
+
+(defun solver-2 (filename)
+ (let ((packages (sort (input filename t) #'compare)))
+ (*
+ (1+ (position '((2)) packages :test #'equal))
+ (1+ (position '((6)) packages :test #'equal)))))
+
+(fiveam:test second
+ (fiveam:is (= 140 (solver-2 "eg-in")))
+ (fiveam:is (= 27648 (solver-2 "input"))))
+
+(fiveam:run-all-tests)