do day 8

2025/src/day08.clj

@@ -0,0 +1,58 @@
+(ns day08
+  (:require input-manager clojure.set
+            [clojure.string :as str]))
+
+(def input (->> (input-manager/get-input 2025 8)
+                (mapv (comp (partial mapv parse-long)
+                            (partial re-seq #"\d+")))))
+(def circuits (into #{} (map hash-set input)))
+
+(defn square [x] (* x x))
+(defn dist-squared [[ax ay az] [bx by bz]]
+  (+ (square (- ax bx))
+     (square (- ay by))
+     (square (- az bz))))
+(def closest-points
+  (->> (for [a input
+             b input
+             :when (not= a b)]
+         #{a b})
+       distinct
+       (map vec)
+       (sort-by (partial apply dist-squared))))
+
+(->> closest-points
+     (take (count input))
+     (reduce (fn [circuits [a b]]
+               (let [circuit-a (first (filter #(% a) circuits))
+                     circuit-b (first (filter #(% b) circuits))]
+                 (if (= circuit-a circuit-b)
+                   circuits
+                   (let [combined (clojure.set/union circuit-a circuit-b)]
+                     (-> circuits
+                         (disj circuit-a)
+                         (disj circuit-b)
+                         (conj combined))))))
+             circuits)
+     (sort-by count)
+     (take-last 3)
+     (map count)
+     (apply *))
+
+(->> (loop [circuits circuits
+            [[a b] & rst] (take 10000 closest-points)]
+       (let [circuit-a (first (filter #(% a) circuits))
+             circuit-b (first (filter #(% b) circuits))]
+         (if (= circuit-a circuit-b)
+           (recur circuits rst)
+           (let [combined (clojure.set/union circuit-a circuit-b)
+                 circuits' (-> circuits
+                               (disj circuit-a)
+                               (disj circuit-b)
+                               (conj combined))]
+             (if (= 1 (count circuits'))
+               [a b]
+               (recur circuits' rst))))))
+     (map first)
+     (apply *))
+