advent-of-code/2025/src/day04.clj
2025-12-04 09:53:17 -10:00

42 lines
1.1 KiB
Clojure

(ns day04
(:require input-manager
core))
(def input (input-manager/get-input 2025 4))
(def grid (core/map-by-coords input))
(def offsets [[-1 -1] [-1 0] [-1 1]
[0 -1] [0 1]
[1 -1] [1 0] [1 1]])
;; part 1
(->> grid
(filter (fn [[_ v]]
(= v \@)))
(map first)
(filter (fn [pos]
(< (count (filter (comp (partial = \@) grid)
(for [o offsets]
(mapv + pos o))))
4)))
count)
;; part 2
(loop [grid grid
acc 0]
(let [locs
(->> grid
(filter (fn [[_ v]]
(= v \@)))
(map first)
(filter (fn [pos]
(< (count (filter (comp (partial = \@) grid)
(for [o offsets]
(mapv + pos o))))
4))))]
(if (empty? locs)
acc
(recur (reduce #(dissoc %1 %2) grid locs)
(+ acc (count locs))))))