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+;; https://adventofcode.com/2021/day/1
+
+; this feels more lisp-y
+; maximum recursion depth reached quickly (in neb-python)
+(func increase-count-recur (inp acc)
+    (branch
+        ((eq? 0 (length (rest inp))) acc)
+        ((> (first (rest inp)) (first inp))
+            (increase-count-recur (rest inp) (+ 1 acc)))
+        (#true
+            (increase-count-recur (rest inp) acc))))
+
+; this works, but i don't like redefining variables
+(func increase-count-iter (inp)
+    (def acc 0)
+    (def prev (first inp))
+    (for-each (rest inp)
+        (if (> _item_ prev)
+            (redef acc (+ 1 acc)))
+        (redef prev _item_))
+    acc)
+
+; (a b c d e) => ((a b) (b c) (c d) (d e))
+(func pairwise (inp)
+    (zip (most inp) (rest inp)))
+
+(func abs (num)
+    (if (< num 0)
+        (* (- 1) num)
+        num))
+
+(func list-subtract (lst)
+    (def ret (apply - lst))
+    (- (/ (abs ret) ret) 1))
+
+; this algorithm is very roundabout
+(func increase-count-iter-2 (inp)
+    (abs (/ (apply + (map list-subtract (pairwise inp))) 2)))
+
+; this is the most ideomatic
+(func increase-count (inp)
+    (length
+        (filter
+            (lambda (x) (apply < x))
+            (pairwise inp))))
+
+(def lines 
+    (map string->int
+        (map strip
+            (read-lines "input.txt"))))
+
+;(print (->string (increase-count-recur lines 0)))
+(print (->string (increase-count-iter lines)))
+(print (->string (increase-count-iter-2 lines)))
+(print (->string (increase-count lines)))