AOC 2020 day 2

day_2.clj

(ns day-2
  (:require [clojure.string :as str]))

(def data (-> "input/day_2.txt"
              (slurp)
              (str/split-lines)))

(defn parse [s]
  (let [[_ pmin pmax pc password]
        (re-matches #"(\d+)-(\d+) ([a-z]): ([a-z]+)" s)]
    {:min      (Integer/parseInt pmin)
     :max      (Integer/parseInt pmax)
     :char     (.charAt pc 0)
     :password password}))

(defn valid-pw? [m]
  (<= (:min m)
      (get (frequencies (:password m)) (:char m) 0)
      (:max m)))

(defn solve-1 []
  (count (filter valid-pw? (map parse data))))

(defn valid-pw-2? [m]
  (let [c1 (.charAt (:password m) (dec (:min m)))
        c2 (.charAt (:password m) (dec (:max m)))]
    (= (set (map #(= (:char m) %) [c1 c2]))
       #{true false})))

(defn solve-2 []
  (count (filter valid-pw-2? (map parse data))))