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-rw-r--r--AoC2022/15/eg-in14
-rw-r--r--AoC2022/15/solver.lisp53
2 files changed, 67 insertions, 0 deletions
diff --git a/AoC2022/15/eg-in b/AoC2022/15/eg-in
new file mode 100644
index 0000000..a612424
--- /dev/null
+++ b/AoC2022/15/eg-in
@@ -0,0 +1,14 @@
+Sensor at x=2, y=18: closest beacon is at x=-2, y=15
+Sensor at x=9, y=16: closest beacon is at x=10, y=16
+Sensor at x=13, y=2: closest beacon is at x=15, y=3
+Sensor at x=12, y=14: closest beacon is at x=10, y=16
+Sensor at x=10, y=20: closest beacon is at x=10, y=16
+Sensor at x=14, y=17: closest beacon is at x=10, y=16
+Sensor at x=8, y=7: closest beacon is at x=2, y=10
+Sensor at x=2, y=0: closest beacon is at x=2, y=10
+Sensor at x=0, y=11: closest beacon is at x=2, y=10
+Sensor at x=20, y=14: closest beacon is at x=25, y=17
+Sensor at x=17, y=20: closest beacon is at x=21, y=22
+Sensor at x=16, y=7: closest beacon is at x=15, y=3
+Sensor at x=14, y=3: closest beacon is at x=15, y=3
+Sensor at x=20, y=1: closest beacon is at x=15, y=3
diff --git a/AoC2022/15/solver.lisp b/AoC2022/15/solver.lisp
new file mode 100644
index 0000000..3d4fafd
--- /dev/null
+++ b/AoC2022/15/solver.lisp
@@ -0,0 +1,53 @@
+(ql:quickload '(fiveam str cl-ppcre arrows uiop))
+
+
+(setf markers
+ (loop for line in (uiop:read-file-lines "eg-in")
+ for (sx sy bx by) = (multiple-value-bind (match values)
+ (cl-ppcre:scan-to-strings "Sensor at x=(-?\\d+), y=\(-?\\d+\): closest beacon is at x=(-?\\d+), y=(-?\\d+)"
+ line)
+ (map 'list #'parse-integer values))
+ nconc (list (cons sx sy) (cons bx by))))
+
+(defun bounds (markers)
+ (list (list
+ (loop for (x . y) in markers minimize x)
+ (loop for (x . y) in markers maximize x))
+ (list
+ (loop for (x . y) in markers minimize y)
+ (loop for (x . y) in markers maximize y))))
+
+(defun grid (bounds)
+ (destructuring-bind ((xmin xmax) (ymin ymax)) bounds
+ (make-array (* (- xmax xmin -1) (- ymax ymin -1)) :initial-element 0 :element-type '(unsigned-byte 2))))
+
+(defun in-grid (bounds)
+ (destructuring-bind ((xmin xmax) (ymin ymax)) bounds
+ (let ((stride (- xmax xmin -1)))
+ (lambda (x y)
+ (when (and (<= xmin x xmax) (<= ymin y ymax))
+ (+ (- x xmin) (* (- y ymin) stride)))))))
+
+
+(defun draw-grid (grid stride)
+ (let ((out (make-string-output-stream)))
+ (loop for elt across grid
+ for idx from 0
+ do (progn (when (= 0 (mod idx stride)) (terpri out))
+ (princ (case elt
+ (0 ".")
+ (1 "S")
+ (2 "B")) out)))
+ (get-output-stream-string out)))
+
+(let* ((bounds (bounds markers))
+ (loc (in-grid bounds))
+ (grid (grid bounds)))
+ (loop for ((sx . sy) (bx . by)) on markers by #'cddr
+ do (progn (princ (list sx sy bx by))
+ (setf (aref grid (funcall loc sx sy)) 1)
+ (setf (aref grid (funcall loc bx by)) 2)))
+ (destructuring-bind ((xmin xmax) a) bounds
+ (princ (draw-grid grid (- xmax xmin -1)))
+ )
+ )