blob: 83d66114c4a134948b08ec3881af12ac97825684 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
(ns org.vuxu.aoc2021.day13
(:require [clojure.string :as str]
[clojure.set :as set]))
(let [[part1 part2] (str/split (slurp "day13") #"\n\n")]
(def dots (set (for [line (str/split-lines part1)]
(mapv parse-long (str/split line #",")))))
(def folds (for [line (str/split-lines part2)]
(let [[xy n] (take-last 2 (str/split line #" |="))]
[(symbol xy)
(parse-long n)]))))
(defn fold [dots [xy n]]
(let [sel (case xy
x 0
y 1)
{a false b true} (group-by #(> (get % sel) n) dots)
a' (for [coord b]
(update coord sel #(- n (- % n))))]
(set/union (set a) (set a'))))
(def part1
(count (fold dots (first folds))))
;; => 716
(defn show [dots]
(str/join "\n"
(reverse
(for [x (range (inc (apply max (map first dots))))]
(apply str
(for [y (range (inc (apply max (map second dots))))]
(if (dots [x y]) "#" ".")))))))
(def part2
(show (reduce fold dots folds)))
(print "---\n" part2 "\n---\n")
;; RPCKFBLR
|
