diff --git a/src/2024/day11.lisp b/src/2024/day11.lisp
index f782a3c..4ff9fb1 100644
--- a/src/2024/day11.lisp
+++ b/src/2024/day11.lisp
@@ -6,30 +6,125 @@
    #:sample-data2
    #:part1
    #:part2
+   #:parse-line
+   #:evolve-stone
+   #:evolve-stones
    ))
 
 (in-package :aoc/2024/11)
 
 
 (defun parse-line (line)
-  line)
+  (mapcar #'parse-integer (cl-ppcre:split " " line)))
 
 
 (defun parse-input (lines)
-  (mapcar #'parse-line lines))
+  (parse-line lines))
 
 (defparameter input-text (first (test-input 2024 11)))
 (defparameter input-data (parse-input input-text))
 
-(defparameter sample-text (aoc:split-lines ""))
+(defparameter sample-text  "125 17")
 (defparameter sample-data 
-              (parse-input sample-text))
+  (parse-input sample-text))
+
+
+(defun n-digits (x)
+  (ceiling (log (1+ x) 10)))
+
+(defun evolve-stone (stone)
+  (let* ((n (n-digits stone))
+	 (split-factor (expt 10 (/ n 2))))
+    (cond
+      ((= 0 stone) (list 1))
+      ((evenp n) (list
+		  (floor (/ stone split-factor))
+		  (mod stone split-factor)))
+      (t (list (* 2024 stone)))))
+  )
+(defun evolve-stones (stones)
+  (loop for stone in stones
+	append (evolve-stone stone)))
+
+(defun evolve-stones-n (stones n)
+  (loop for i from 1 to n
+	do (setf stones (evolve-stones stones))
+	finally (return stones)))
+
+(defun number-stones-after-n-evolutions (stones n)
+  (length (evolve-stones-n stones n))
+  )
+
+
+(defparameter stone-map-25-cache (make-hash-table :size 1000))
+
+(defun map-stone-25 (stone)
+  (let ((rslt (gethash stone stone-map-25-cache)))
+    (or rslt
+	(let ((stones (evolve-stones-n (list stone) 25))
+	      (stone-map (make-hash-table)))
+	  (loop for s in stones
+		do (incf (gethash s stone-map 0)))
+	  (setf (gethash stone stone-map-25-cache) stone-map)))))
+
+(defun merge-stone-map (map1 map2 &optional (multiplier 1))
+  (let ((result (copy-hash-table map1)))
+    (loop
+      for k being the hash-keys of map2
+      for v being the hash-values of map2
+      do (incf (gethash k result 0) (* v multiplier)))
+    result))
+
+
+(defun evolve-stone-map-25 (stone-map)
+  (let ((result (make-hash-table :size 1000)))
+    (loop
+      for k being the hash-keys of stone-map
+      for v being the hash-values of stone-map
+      do (setf result (merge-stone-map result (map-stone-25 k) v)))
+    result))
+
+(defun stones-to-stone-map (stones)
+  (let ((result (make-hash-table :size (length stones))))
+    (loop
+      for k in stones
+      do (setf (gethash k result) 1))
+    result))
+
+(defun total-stones (stone-map)
+  (loop for v being the hash-values of stone-map sum v))
+
+(defparameter stone-map-cache (make-hash-table :size 1000))
+(defun map-stone (stone)
+  (let ((rslt (gethash stone stone-map-cache)))
+    (or rslt
+	(let ((stones (evolve-stone stone))
+	      (stone-map (make-hash-table)))
+	  (loop for s in stones
+		do (incf (gethash s stone-map 0)))
+	  (setf (gethash stone stone-map-cache) stone-map)))))
+
+(defun evolve-stone-map (stone-map)
+  (let ((result (make-hash-table :size 1000)))
+    (loop
+      for k being the hash-keys of stone-map
+      for v being the hash-values of stone-map
+      do (setf result (merge-stone-map result (map-stone k) v)))
+    result))
+
+(defun evolve-stone-map-n (stone-map n)
+  (loop
+    for i from 1 to n
+    with sm = stone-map
+    do (setf sm (evolve-stone-map sm))
+    finally (return sm)))
 
 (defun part1 (data)
-  nil)
+  (format nil "~A" (total-stones (evolve-stone-map-n (stones-to-stone-map data) 25))))
 
 (defun part2 (data)
-  nil)
+  (format nil "~A" (total-stones (evolve-stone-map-n (stones-to-stone-map data) 75))))
+
 
 (defun solve-day ()
   (format t "part1: ~A~%" (part1 input-data))
diff --git a/tests/2024/day11-test.lisp b/tests/2024/day11-test.lisp
index f7fccf6..10f4474 100644
--- a/tests/2024/day11-test.lisp
+++ b/tests/2024/day11-test.lisp
@@ -7,20 +7,41 @@
                                         ;:parent suite-2024
              )
 
-(define-test test-foo
-             :parent suite-2024-11
-             ) 
+(define-test test-parse-line
+  :parent suite-2024-11
+  (is equal '(125 17) (parse-line "125 17"))
+  ) 
 
 
-(define-test test-bar
-             :parent suite-2024-11
-             )
+
+(defparameter example-evolution
+  '((125 17)
+    (253000 1 7)
+    (253 0 2024 14168)
+    (512072 1 20 24 28676032)
+    (512 72 2024 2 0 2 4 2867 6032)
+    (1036288 7 2 20 24 4048 1 4048 8096 28 67 60 32)
+    (2097446912 14168 4048 2 0 2 4 40 48 2024 40 48 80 96 2 8 6 7 6 0 3 2)))
+
+(define-test test-evolve-stone
+  :parent suite-2024-11
+  (is equal '(1) (evolve-stone 0))
+  (is equal '(9 9) (evolve-stone 99))
+  (is equal '(2024) (evolve-stone 1)))
+
+(define-test test-evolve-stones
+  :parent suite-2024-11
+  (loop
+    for case in example-evolution
+    for expected in (subseq example-evolution 1)
+    do (is equal expected (evolve-stones case))    )
+  )
 
 
 
 (define-test+run test-part1
-                 :parent suite-2024-11
-                 (is equal nil (part1 sample-data)))
+  :parent suite-2024-11
+  (is equal "55312" (part1 sample-data)))
 
 (define-test+run test-part2
                  :parent suite-2024-11