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do day 7

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Adam Jeniski 2025-12-06 20:03:01 -10:00
parent ac6c0097e6
commit 4e548d4d40
1 changed files with 55 additions and 0 deletions
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2025/src/day07.clj Normal file
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(ns day07
(:require input-manager
core))
(def input (input-manager/get-input 2025 7))
(def start ((core/map-to-coords input) \S))
(def grid (core/map-by-coords input))
(def NUM_ROWS (count input))
(defn left [loc] (update loc 1 dec))
(defn right [loc] (update loc 1 inc))
(defn down [loc] (update loc 0 inc))
(defn splitter? [loc] (= (grid loc) \^))
;; part 1
(->> (range NUM_ROWS)
(reduce (fn [{:keys [acc search-locs]} _]
(if (empty? search-locs)
(reduced acc)
(let [next-locs (map down search-locs)
splitters (filter splitter? next-locs)
next-locs (-> #{}
(into (filter (complement splitter?) next-locs))
(into (mapcat (juxt left right) splitters)))]
{:acc (into acc splitters)
:search-locs next-locs})))
{:acc #{}, :search-locs #{start}})
:acc
count)
(defn left-entry [[loc cnt]] [(left loc) cnt])
(defn right-entry [[loc cnt]] [(right loc) cnt])
(defn splitter-entry? [[loc _]] (= (grid loc) \^))
(defn join-flows [flows]
(reduce (fn [acc [loc cnt]]
(if (acc loc)
(update acc loc + cnt)
(assoc acc loc cnt)))
{}
flows))
;; part 2
(->> (range NUM_ROWS)
(reduce (fn [{:keys [acc search-locs]} _]
(if (empty? search-locs)
(reduced acc)
(let [next-locs (update-keys search-locs down)
splitters (filter splitter-entry? next-locs)
next-locs (join-flows (concat (filter (complement splitter-entry?) next-locs)
(mapcat (juxt left-entry right-entry) splitters)))]
{:acc (apply + acc (map (fn [[_ cnt]] cnt) splitters))
:search-locs next-locs})))
{:acc 1, :search-locs {start 1}})
:acc)