Advent of Code - 2018 - Day 1

aoc1.clj

(ns aoc1)

(defn calibrate-1 
  "Simple solution for part 1 of AoC 2018 Day 1"
  [input-file]
  (let [raw-input (slurp input-file)
        freqs (map #(Integer. %) (clojure.string/split-lines raw-input))]
    (reduce + freqs)))

;; Below contents are from part 2, which didn't work well.
(defn frequency-adjustments [freqs]
  (reductions + (cycle freqs)))

(defn calibrate [freqs]
  (loop [n 2]
    (let [steps (take n (frequency-adjustments freqs))
          step-counts (frequencies (rest steps))
          repeats (filter (fn [[k v]] (if (= v 2) k)) step-counts)]
      (if-not (empty? repeats)
        (first (keys repeats))
        (recur (inc n))))))

;; Part 2.5, which was co-opted from https://www.reddit.com/r/adventofcode/comments/a20646/2018_day_1_solutions/eau9gjm/
(defn calibrate2 [freqs]
  (loop [xs (cycle freqs) seen #{} total 0]
    (if (contains? seen total)
      total
      (recur (rest xs) (conj seen total) (+ total (first xs))))));