advent-of-code/year2021/day3/part1.clj

(require '[clojure.string :as str])

(->> "./in"
     (slurp)
     (str/split-lines)
     (map (fn [l] (map #(if (= % \1) 1 0) l)))
     (apply (partial map +))
     (map #(if (< % 500) \1 \0))
     (str/join)
     (#(Integer/parseInt % 2))
     (#(* % (bit-xor % (dec (int (Math/pow 2 12))))))
     (println)
     )

; (->> input data file name
;      read in entire contents
;      split contents into array of lines
;      for each line, transform characters '1'/'0' to numbers
;      build sum array using the lines
;      convert back to array of characters
;      join characters into single string
;      convert binary string to a number (gamma)
;      multiply gamma by its bit-inverse (bit length hard-coded)
;      print results