part 1 day 9

2024/src/day09.clj

@@ -0,0 +1,32 @@
+(ns day09
+  (:require
+   [core :as c]
+   [input-manager :refer [get-input]]))
+
+(defn partition-by-counts [counts coll]
+  (loop [[c & cs] counts
+         acc []
+         coll coll]
+    (cond
+      (nil? c) acc
+      :else (let [[a b] (split-at c coll)]
+              (recur cs (conj acc a) b)))))
+
+(def input (->>
+            ; (first (get-input 9))
+            "2333133121414131402"
+            (map str)
+            (map parse-long)))
+
+(def smol-nums (->> input (take-nth 2) (into [])))
+(def smol-spaces (->> input rest (take-nth 2) (into [])))
+
+;; part 1
+(let [forward (map-indexed #(repeat %2 %1) smol-nums)]
+  (->> forward reverse flatten
+       (partition-by-counts smol-spaces)
+       (interleave forward)
+       flatten
+       (take (reduce + smol-nums))
+       (map-indexed *)
+       (reduce +)))