--- /dev/null
+(ns adventofcode2019.day08
+ [:require [adventofcode2019.lib :refer :all]
+ [clojure.core.match :refer [match]]])
+
+(def combine-layers
+ "Binary operation on the pixels of two layers, the first above the second."
+ #(match [%1 %2]
+ [0 _] 0
+ [1 _] 1
+ [2 p] p))
+
+(defn day08 []
+ (let [input (mapv parse-int (get-list-from-file (input-file) #""))
+ layer-size (* 25 6)
+ count-num #(count (filter (hash-set %1) %2))
+ layers (partition layer-size input)
+ fewest-zeroes (apply (partial min-key (partial count-num 0))
+ layers)
+ layered-image (reduce #(mapv combine-layers %1 %2) layers)
+ to-ascii #(match % 0 \u0020 ; 0s are spaces, 1s are full-block
+ 1 \u2588)]
+ (part1 (* (count-num 1 fewest-zeroes)
+ (count-num 2 fewest-zeroes)))
+ (part2 "see below")
+ (run! println (partition 25 (map to-ascii layered-image)))))