Day 18

Author: abyala

docs/day20.md

@@ -50,7 +50,7 @@ For what it's worth, in the sample problem, `(get alg 0)` is zero, so the border
 ```clojure
 (defn border-seq [alg]
   (let [block-of {dark-pixel 0, light-pixel 511}]
-    (iterate #(-> % block-of alg) 0)))
+    (iterate (comp alg block-of) dark-pixel)))
 ```
 
 Now we can create a `migrate-image` function, which takes in the algorithm, the value of all border coordinates, and 

src/advent_2021_clojure/day20.clj

@@ -16,7 +16,7 @@
 
 (defn border-seq [alg]
   (let [block-of {dark-pixel 0, light-pixel 511}]
-    (iterate #(-> % block-of alg) 0)))
+    (iterate (comp alg block-of) dark-pixel)))
 
 (defn next-value-at [alg border image coords]
   (->> (point/surrounding true coords)