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65 lines
1.4 KiB
Clojure
65 lines
1.4 KiB
Clojure
3 years ago
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(def input-map
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(->> (slurp "./in")
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(clojure.string/split-lines)
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(mapv vec)
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(mapv (partial mapv #(- (int %) 48)))
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))
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(defn basin-bottom-single? [a b]
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(if (or (nil? a) (nil? b) (< a b)) 1 0))
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(defn basin-continues? [a b]
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(and (some? b) (not= b 9) (> b a)))
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(defn basin-bottom? [hmap p adj]
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(= 4
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(apply +
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(map
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#(basin-bottom-single?
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(get-in hmap p)
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(get-in hmap %))
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adj
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))))
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(defn get-adj [y x]
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[[(dec y) x]
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[(inc y) x]
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[y (dec x)]
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[y (inc x)]])
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(defn find-basin [hmap y x adj]
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(let [res (reduce
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#(if
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(basin-continues? (get-in hmap [y x])
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(get-in hmap %2))
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(conj %1 %2)
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%1)
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[]
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adj
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)]
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(if (empty? res)
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[]
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(apply
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(partial concat res)
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(map
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#(find-basin hmap (first %) (second %) (apply get-adj %))
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res))
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)
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)
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)
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(println
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(apply *
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(take 3
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(sort >
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(filter
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pos?
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(for [y (range 0 (count input-map))
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x (range 0 (count (first input-map)))]
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(let [adj (get-adj y x)]
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(if (basin-bottom? input-map [y x] adj)
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(count (distinct (concat [[y x]] (find-basin input-map y x adj))))
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0
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))))))))
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