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(require '[clojure.core.reducers :as r])
(require 'clojure.string)
(defn build-scanner-reports [input-lines]
(loop [scanners [] rem-input input-lines]
(if (empty? rem-input)
scanners
(let [[this nxt] (split-with (comp not empty?) rem-input)]
(recur
(->> (rest this)
(map #(read-string (clojure.string/join ["[" % "]"])))
(conj scanners))
(rest nxt))))))
(defn all-orientations [[x y z]]
(map (fn [[i j k]] [(* x i) (* y j) (* z k)])
'([1 1 1] [-1 1 1] [1 -1 1] [-1 -1 1] [1 1 -1] [-1 1 -1] [1 -1 -1] [-1 -1 -1])))
(defn group-orientations [lst]
(for [i (range 0 8)] (map #(nth % i) lst)))
(defn scanner-orientations [scanner]
(group-orientations (map all-orientations scanner)))
(defn add-coordinate [[a b c] [d e f]] [(+ a d) (+ b e) (+ c f)])
(defn add-coordinate-lists [l1 l2]
(for [i (range 0 (count l1))]
(for [j (range 0 (count l2))]
(add-coordinate (nth l1 i) (nth l2 j)))))
(defn compare-scanners [s1 s2]
(let [o1 [s1];(scanner-orientations s1)
o2 (scanner-orientations s2)]
(for [o o1 p o2]
(add-coordinate-lists o p))))
(defn check-beacon-coord [scanner coord index]
(not (empty? (filter #(= coord %) (map #(nth % index) scanner)))))
(defn beacon-coord-match? [req coord compared-scanners]
(let [cnt (count (first (first compared-scanners)))]
(< (dec req)
(reduce
(fn [tot n]
(cond-> tot
(and (< tot req)
(reduce
#(or %1 %2)
(map #(check-beacon-coord % coord n) compared-scanners)))
inc))
0
(range 0 cnt)))))
(->> (slurp "./in")
(clojure.string/split-lines)
(build-scanner-reports)
((fn [scanners]
(for [s1i (range 0 (count scanners))
s2 (drop (inc s1i) scanners)
:let [res (compare-scanners (nth scanners s1i) s2)]]
(let [cnt (count (first (first res)))]
(into '()
(r/fold
r/cat
(fn [final c]
(cond-> final
(beacon-coord-match? 4 c res)
(r/append! c)))
(into [] (distinct (nth (iterate (partial reduce concat) res) 2)))))))))
(println))
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