init day 8

2024/bb.edn

@@ -1,3 +1,4 @@
-{:deps {org.clojure/clojure {:mvn/version "1.12.0"}}
+{:deps {org.clojure/clojure {:mvn/version "1.12.0"}
+        org.clojure/math.combinatorics {:mvn/version "0.3.0"}}
  :paths ["src"]
  :tasks {}}

2024/input/8.txt

@@ -0,0 +1,50 @@
+........5................r..................B.....
+....................................V..B..........
+...........................................B......
+r..................C....................Y......N..
+............................C.....................
+vb.r........9......x..................7...........
+..v........C.........................U...7.N..6...
+5............9..................n.B...............
+....r........4....................0.....K.....Y...
+..4...C............7.......U..........6...........
+......4z....................n.......U....6........
+..............b...........N..........n............
+.......9............x.....V..............K........
+.....v......................................2.....
+.....V........Z........n..........................
+....z..........................VU......K..........
+...b....z..............................Y..........
+.z.......Z..................................K.....
+..b.................................7.............
+.4x...............................................
+.h.......................5........................
+.................................g................
+..............9....0.........c................d...
+......h.................u.............c........2.d
+.....................8........N.....c...2.T.......
+......Z..h.......................................c
+........H........d................................
+........................................d.........
+.Z........................................k.......
+...............................T...............6..
+q..............Q...X..O............2..............
+..............................O.8......D..........
+........X............................O............
+.........t......................T.................
+..........................t...8.......Q......u....
+.................Q.....O..........................
+..........hj.......o..............JR....u.........
+..........X..........ot.........3.R...............
+.......J.............y.....3.....................g
+............y..J.Xj......R..........G.............
+.....................t.........H.....D..g...G.....
+........J.......o......y.......k..................
+..................1...............................
+.....................3....k.......q.........1.....
+...........v......................3k..............
+...................1......Q...H............G......
+.............1y......T............j...............
+......0............8..................D........u..
+.............................G....D...o....q......
+...............j.0...H............................

2024/src/day08.clj

@@ -0,0 +1,44 @@
+(ns day08
+  (:require
+   [core :as c]
+   [input-manager :refer [get-input]]
+   [clojure.math.combinatorics :as combo]
+   [clojure.set :refer [union]]))
+
+(def input (mapv vec (get-input 8)))
+
+(defn get-char [[row col]]
+  (get (get input row) col))
+
+(def locs (->> input
+               c/get-coords
+               (map #(vector (get-char %) %))
+               (group-by first)
+               (#(dissoc % \.))
+               (#(update-vals % (partial mapv second)))))
+
+(defn get-antinode-pos [[x1 y1] [x2 y2] multiplier]
+  (vector (+ x1 (* multiplier (- x2 x1)))
+          (+ y1 (+ (* multiplier (- y2 y1))))))
+
+(defn get-antinodes [[a b]]
+  (filterv #(get-char %) [(get-antinode-pos a b 2) (get-antinode-pos b a 2)]))
+
+;; part 1
+(->> locs
+     vals
+     (map #(->> (combo/combinations % 2) (mapcat get-antinodes) set))
+     (reduce union)
+     (count))
+
+(defn get-antinodes-2 [[a b]]
+  (concat (take-while get-char (map #(get-antinode-pos a b %) (range)))
+          (take-while get-char (map #(get-antinode-pos b a %) (range)))))
+
+;; part 2
+(->> locs
+     vals
+     (map #(->> (combo/combinations % 2) (mapcat get-antinodes-2) set))
+     (reduce union)
+     (count))
+