src/adventofcode2019/day08.clj

   1 (ns adventofcode2019.day08
   2     [:require [adventofcode2019.lib :refer :all]
   3               [clojure.string :as str]
   4               [clojure.core.match :refer [match]]])
   5
   6 (defn day08 []
   7   (let [input (map parse-int (get-list-from-file (input-file) #""))
   8         [image-x image-y] [25 6]
   9         layer-size (* image-x image-y)
  10
  11         count-num #(count (filter (hash-set %1) %2))
  12         combine-layers #(match [%1 %2] [0 _] 0
  13                                        [1 _] 1
  14                                        [2 p] p)
  15         to-text #(match % 0 \u0020 ; 0s are spaces, 1s are full-block
  16                           1 \u2588)
  17         layers (partition layer-size input)
  18
  19         fewest-zeroes (apply (partial min-key (partial count-num 0)) layers)
  20         layered-image (reduce #(map combine-layers %1 %2) layers)]
  21     (part1 (* (count-num 1 fewest-zeroes)
  22               (count-num 2 fewest-zeroes)))
  23     (part2 "see below")
  24     (run! println (->> layered-image
  25                        (map to-text)
  26                        (partition image-x)
  27                        (map str/join)))))