4 files changed, 210 insertions, 0 deletions
diff --git a/2021/14/code.tl b/2021/14/code.tl
new file mode 100644
index 0000000..0af2ac7
--- /dev/null
+++ b/2021/14/code.tl
@@ -0,0 +1,48 @@
+(defstruct polym ()
+  input
+  rewrites
+  (memo (hash)))
+
+(defun read-input (: (name "input"))
+  (let ((po (new polym)))
+    (each ((line (file-get-lines name)))
+      (match-case line
+        (`@{x 1}@{y 1} -> @z` (push ^((,(intern-fb x)
+                                       ,(intern-fb y))
+                                      ,(intern-fb z))
+                                po.rewrites))
+        (`@{x #/.+/}` -> (set po.input (flow x
+                                         (tuples 1)
+                                         (mapcar intern-fb))))))
+    po))
+
+(defmeth polym rec1 (po pair depth : (leftmost t))
+  (let ((key ^(,pair ,depth ,leftmost)))
+    (condlet
+      (((re [po.memo key]))
+       re)
+      (((rw (and (plusp (pdec depth))
+                 [find pair po.rewrites : car])))
+       (tree-bind ((x y) z) rw
+         (let ((lhist po.(rec1 ^(,x ,z) depth leftmost))
+               (rhist po.(rec1 ^(,z ,y) depth nil)))
+           (set [po.memo key]
+                [hash-uni lhist rhist +]))))
+      (leftmost
+        (hash-zip pair '(1 1)))
+      (t
+        (hash-zip (cdr pair) '(1))))))
+
+(defmeth polym rec (po pairs depth : (leftmost t))
+  (let ((hist (hash)))
+    (each ((p pairs)
+           (c 0))
+      (let ((rhist po.(rec1 p depth (zerop c))))
+        (set hist [hash-uni hist rhist +])))
+    hist))
+
+(defun solve (: (name "input") (depth 10))
+  (let* ((po (read-input name))
+         (hist po.(rec (tuples* 2 po.input) depth)))
+    (- (cdr [find-max hist : cdr])
+       (cdr [find-min hist : cdr]))))
diff --git a/2021/14/codes.tl b/2021/14/codes.tl
new file mode 100644
index 0000000..dcaccba
--- /dev/null
+++ b/2021/14/codes.tl
@@ -0,0 +1,42 @@
+(defstruct polym ()
+  input
+  rewrites
+  (memo (hash)))
+
+(defun read-input (: (name "input"))
+  (let ((po (new polym)))
+    (each ((line (file-get-lines name)))
+      (match-case line
+        (`@a -> @b` (push `@a@b` po.rewrites))
+        (`@{a 1}@b` (set po.input `@a@b`))))
+    po))
+
+(defmeth polym rec1 (po pair depth : (leftmost t))
+  (placelet ((memo [po.memo ^(,pair ,depth ,leftmost)]))
+    (condlet
+      (((re memo))
+       re)
+      (((rw (and (plusp (pdec depth))
+                 [find pair po.rewrites starts-with])))
+       (match `@{x 1}@{y 1}@{z 1}` rw
+         (let ((lhist po.(rec1 `@x@z` depth leftmost))
+               (rhist po.(rec1 `@z@y` depth nil)))
+           (set memo [hash-uni lhist rhist +]))))
+      (leftmost
+        (set memo (hash-zip pair '(1 1))))
+      (t
+        (set memo (hash-zip (rest pair) '(1)))))))
+
+(defmeth polym rec (po pairs depth : (leftmost t))
+  (let ((hist (hash)))
+    (each ((p pairs)
+           (c 0))
+      (let ((rhist po.(rec1 p depth (zerop c))))
+        (set hist [hash-uni hist rhist +])))
+    hist))
+
+(defun solve (: (name "input") (depth 10))
+  (let* ((po (read-input name))
+         (hist po.(rec (tuples* 2 po.input) depth)))
+    (- (cdr [find-max hist : cdr])
+       (cdr [find-min hist : cdr]))))
diff --git a/2021/14/input b/2021/14/input
new file mode 100644
index 0000000..4711af4
--- /dev/null
+++ b/2021/14/input
@@ -0,0 +1,102 @@
+VCOPVNKPFOOVPVSBKCOF
+
+NO -> K
+PO -> B
+HS -> B
+FP -> V
+KN -> S
+HV -> S
+KC -> S
+CS -> B
+KB -> V
+OB -> V
+HN -> S
+OK -> N
+PC -> H
+OO -> P
+HF -> S
+CB -> C
+SB -> V
+FN -> B
+PH -> K
+KH -> P
+NB -> F
+KF -> P
+FK -> N
+FB -> P
+FO -> H
+CV -> V
+CN -> P
+BN -> N
+SC -> N
+PB -> K
+VS -> N
+BP -> P
+CK -> O
+PS -> N
+PF -> H
+HB -> S
+VN -> V
+OS -> V
+OC -> O
+BB -> F
+SK -> S
+NF -> F
+FS -> S
+SN -> N
+FC -> S
+BH -> N
+HP -> C
+VK -> F
+CC -> N
+SV -> H
+SO -> F
+HH -> C
+PK -> P
+NV -> B
+KS -> H
+NP -> H
+VO -> C
+BK -> V
+VV -> P
+HK -> B
+CF -> B
+BF -> O
+OV -> B
+OH -> C
+PP -> S
+SP -> S
+CH -> B
+OF -> F
+NK -> F
+FV -> F
+KP -> O
+OP -> O
+SS -> P
+CP -> H
+BO -> O
+KK -> F
+HC -> N
+KO -> V
+CO -> F
+NC -> P
+ON -> P
+KV -> C
+BV -> K
+HO -> F
+PV -> H
+VC -> O
+NH -> B
+PN -> H
+VP -> O
+NS -> N
+NN -> S
+BS -> H
+SH -> P
+VB -> V
+VH -> O
+FH -> K
+FF -> H
+SF -> N
+BC -> H
+VF -> P
diff --git a/2021/14/testinput b/2021/14/testinput
new file mode 100644
index 0000000..b5594dd
--- /dev/null
+++ b/2021/14/testinput
@@ -0,0 +1,18 @@
+NNCB
+
+CH -> B
+HH -> N
+CB -> H
+NH -> C
+HB -> C
+HC -> B
+HN -> C
+NN -> C
+BH -> H
+NC -> B
+NB -> B
+BN -> B
+BB -> N
+BC -> B
+CC -> N
+CN -> C