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Diffstat (limited to 'AoC2023/day07/solver.lisp')
| -rw-r--r-- | AoC2023/day07/solver.lisp | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/AoC2023/day07/solver.lisp b/AoC2023/day07/solver.lisp new file mode 100644 index 0000000..3a1fe8a --- /dev/null +++ b/AoC2023/day07/solver.lisp @@ -0,0 +1,80 @@ +(ql:quickload '(fiveam arrows trivia str)) +(defpackage #:day07 + (:use #:cl) + (:local-nicknames (#:f #:fiveam))) + +(in-package :day07) + +(defparameter eg-input "32T3K 765 +T55J5 684 +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 hand-type (str) + (trivia:match (occurences str) + ((list 5) 5) + ((list 4 1) 4) + ((list 3 2) 3) + ((list 3 1 1) 2) + ((list 2 2 1) 1) + ((list 2 1 1 1) 0) + ((list 1 1 1 1 1) -1))) + +(defun card-strength (card) + (position card "23456789TJQKA")) + +(defun card-< (a b) + (< (card-strength a) (card-strength b))) + +(defun hand-< (a b) + (let ((a-t (hand-type a)) + (b-t (hand-type b))) + (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)))))) + +(f:test partial + (f:is + (equal '(3 1 1) + (occurences "QJQAQ"))) + (f:is (hand-< "2AAAA" "33332")) + (f:is (hand-< "77788" "77888")) + (f:is (hand-< "77788" "77778"))) + +(defun parse-input (str) + (let ((data (arrows:->> + (ppcre:split "\\s" str) + (remove-if #'str:empty?)))) + (loop for (hand bid) on data by #'cddr + collect (cons hand (parse-integer bid))))) + +(defun total-win (sorted-hands) + (loop for (hand . bid) in sorted-hands + for c from 1 + sum (* c bid))) + +(defun solver1 (lines) + (arrows:-> + (parse-input lines) + (sort #'hand-< :key #'car) + (total-win))) +(f:test solutions + (f:is + (= 6440 + (solver1 eg-input))) + (f:is + (= 253205868 + (solver1 + (uiop:read-file-string "input"))))) |