Advent Of Code - 2019 - DAY 4 #adventOfCode2019

aoc_day4.clj

(ns cljbrave.day4)

(defn digits
  [n]
  (loop [result (list)
         n n]
    (if (pos? n)
      (recur (conj result (rem n 10))
             (quot n 10))
      result)))

(defn adjacent?
  [n]
  (true? (reduce (fn [prev v] (if (= prev v) (reduced true) v)) (digits n))))

(defn adjacent-larger?
  [n]
  (some #(= 2 (count %)) (partition-by identity (digits n))))

(defn non-decrease?
  [n]
  (apply <= (digits n)))

(defn possible-password?
  [n]
  (and
    (adjacent? n)
    (non-decrease? n)))

(defn possible-password-enhanced?
  [n]
  (and
    (adjacent-larger? n)
    (non-decrease? n)))

(defn number-of-possible-password
  []
  (count (filter possible-password-enhanced? (range 124075 580770))))

(println (number-of-possible-password))