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28 lines
815 B
Clojure
28 lines
815 B
Clojure
3 years ago
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(require '[clojure.string :as str])
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(def input (->> (slurp "./in")
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str/split-lines
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((juxt
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first
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(fn [lines]
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(->> lines
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(drop 2)
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(map #(str/split % #" -> "))
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(flatten)
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(apply (partial assoc {}))
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))))))
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(defn grow-polymer [polymer insertion-rules]
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(str/join
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(cons
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(first polymer)
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(mapcat (juxt insertion-rules second)
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(for [i (range 0 (dec (count polymer)))]
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(subs polymer i (+ i 2)))))))
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(def growth-seq (iterate #(grow-polymer % (second input)) (first input)))
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(let [freqs (vals (frequencies (nth growth-seq 10)))]
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(println (- (apply max freqs) (apply min freqs))))
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