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refactor, add more comments

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This commit is contained in:
Adam Jeniski 2023-12-03 13:22:46 -05:00
parent d6a9747af2
commit 34a17e5edb
1 changed files with 32 additions and 29 deletions
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61
2023/src/day03.clj
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@ -4,6 +4,8 @@
[core :refer [get-puzzle-input re-seq-pos]])) [core :refer [get-puzzle-input re-seq-pos]]))
(def lines (get-puzzle-input 3)) (def lines (get-puzzle-input 3))
;; a hash-map of [row-idx col-idx] to char
(def char-map (def char-map
(->> lines (->> lines
(map-indexed (fn [row-idx line] (map-indexed (fn [row-idx line]
@ -34,36 +36,37 @@
(map #(Integer/parseInt (nth % 2))) (map #(Integer/parseInt (nth % 2)))
(reduce +)) (reduce +))
;; part 2
;; stars is a list of [[star-row-idx star-col-idx] "num"] ;; stars is a list of [[star-row-idx star-col-idx] "num"]
;; stars is list of each * char found touching a number when iterating by nums ;; stars is list of each * char found touching a number when iterating by nums
(let [stars (->> (parse-nums lines) (def stars (->> (parse-nums lines)
(map (fn touching-stars [[row-idx col-idx s]] (map (fn touching-stars [[row-idx col-idx s]]
(let [length (count s)] (let [length (count s)]
(->> (for [r [(dec row-idx) row-idx (inc row-idx)] (->> (for [r [(dec row-idx) row-idx (inc row-idx)]
c (range (dec col-idx) (+ col-idx length 1))] c (range (dec col-idx) (+ col-idx length 1))]
[[r c] (char-map [r c])]) [[r c] (char-map [r c])])
(filter #(not (nil? (second %)))) (filter #(not (nil? (second %))))
(filter #(= \* (second %))) (filter #(= \* (second %)))
(map #(vector % s)))))) (map #(vector % s))))))
(filter seq) (filter seq)
(mapcat identity) (mapcat identity)
(map #(vector (ffirst %) (second %)))) (map #(vector (ffirst %) (second %)))))
;; gears is a set of [star-row-idx star-col-idx] ;; gears is a set of [star-row-idx star-col-idx]
;; gears is a list of each * char that is touching exactly 2 nums ;; gears is a list of each * char that is touching exactly 2 nums
gears (->> stars (def gears (->> stars
(map first) (map first)
(frequencies) (frequencies)
(filter #(= (second %) 2)) (filter #(= (second %) 2))
(map first) (map first)
(into #{}))] (into #{})))
(->> stars
(group-by first) ;; part 2
(filter #(gears (first %))) (->> stars
(map #(update % 1 (partial map second))) (group-by first)
(map second) (filter #(gears (first %)))
(map (partial map #(Integer/parseInt %))) (map #(second (update % 1 (partial map second))))
(map (partial reduce *)) (map (partial map #(Integer/parseInt %)))
(reduce +))) (map (partial reduce *))
(reduce +)
)