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-rw-r--r--AoC2023/day12/solver.lisp72
1 files changed, 46 insertions, 26 deletions
diff --git a/AoC2023/day12/solver.lisp b/AoC2023/day12/solver.lisp
index ce196c9..c93a351 100644
--- a/AoC2023/day12/solver.lisp
+++ b/AoC2023/day12/solver.lisp
@@ -11,30 +11,50 @@
????.######..#####. 1,6,5
?###???????? 3,2,1")
+(defun parse-line (line)
+ (destructuring-bind (row . damage-list)
+ (cl-ppcre:split "[\\s,]" line)
+ (cons row (mapcar #'parse-integer damage-list))))
-(destructuring-bind (row . damage-list)
- (cl-ppcre:split "[\\s,]" "???.###. 1,1,3")
- (setf damage-list (mapcar #'parse-integer damage-list))
- (labels ((options (row-idx damage-group)
- (cond
- ;; commited to all options
- ((= damage-group (length damage-list))
- ;; If still damaged springs are left, then
- ;; it was a wrong arrangement, otherwise counts
- (if (find damaged (subseq row row-idx)) 0 1))
- ;; Not enough space to fit the current damaged-group
- ((<= (length row) (+ row-idx (elt damage-list damage-group))) 0)
- ;; Probe options. Either commit to a damage-group at row-idx or skip position
- (t
- (let* ((damaged-count (elt damage-list damage-group))
- (next-slot (+ row-idx damaged-count)))
- (+ (if (not (or (find operational (subseq row row-idx next-slot))
- (char-equal damaged (aref row next-slot))))
- ;; commits to the damage group, because in condition it has space
- ;; Skips one slot, because it checked that it wasn't damaged
- (options (1+ next-slot) (1+ damage-group))
- 0)
- (if (not (char-equal damaged (aref row row-idx)))
- (options (1+ row-idx) damage-group)
- 0)))))))
- (options 0 0)))
+(defun solve-row (line)
+ (destructuring-bind (row . damage-list) (parse-line line)
+ (labels ((options (row-idx damage-group)
+ (cond
+ ;; commited to all options
+ ((= damage-group (length damage-list))
+ ;; If commited to all slots too, is valid option
+ ;; If still damaged springs are left, then
+ ;; it was a wrong arrangement, otherwise counts
+ (cond ((>= row-idx (length row)) 1)
+ ((find damaged (subseq row row-idx)) 0)
+ (1)))
+ ;; Not enough space to fit the current damaged-group
+ ((< (length row) (+ row-idx (elt damage-list damage-group))) 0)
+ ;; Probe options. Either commit to a damage-group at row-idx or skip position
+ (t
+ (let* ((damaged-count (elt damage-list damage-group))
+ (next-slot (+ row-idx damaged-count)))
+ (+ (if (not (or (find operational (subseq row row-idx next-slot))
+ (and (< next-slot (length row))
+ (char-equal damaged (aref row next-slot)))))
+ ;; commits to the damage group, because in condition it has space
+ ;; Skips one slot, because it checked that it wasn't damaged
+ (options (1+ next-slot) (1+ damage-group))
+ 0)
+ (if (not (char-equal damaged (aref row row-idx)))
+ (options (1+ row-idx) damage-group)
+ 0)))))))
+ (options 0 0))))
+
+(solve-row "???.### 1,1,3")
+
+(fiveam:test partial
+ (loop for line in (cl-ppcre:split "\\n" eg-input)
+ for solution in '(1 4 1 1 4 10) do
+ (fiveam:is (= solution (solve-row line)))) )
+
+(fiveam:test solutions
+ (fiveam:is (= 7090
+ (reduce #'+
+ (uiop:read-file-lines "input")
+ :key #'solve-row))))