do day 11

2023/src/day11.clj

@@ -0,0 +1,53 @@
+(ns day11
+  (:require [core :refer [get-puzzle-input]]))
+
+(def input (get-puzzle-input 11))
+
+(def empty-rows
+  (->> input
+       (map-indexed vector)
+       (filter (fn [[_ line]]
+                 (every? #(= \. %) line)))
+       (map first)))
+
+(def empty-cols
+  (->> input first count range
+       (filter (fn [n] (every? #(= \. %)
+                               (map #(.charAt % n) input))))))
+
+(defn gen-hash-locations [modifier]
+  (->> input
+       (map-indexed (fn [row line]
+                      (map-indexed (fn [col c]
+                                     [[row col] c])
+                                   line)))
+       (apply concat)
+       (filter #(= \# (second %)))
+       (map first)
+       (map (fn [[row col]]
+              [(+ row (* (dec modifier)
+                         (count (filter #(> row %) empty-rows))))
+               (+ col (* (dec modifier)
+                         (count (filter #(> col %) empty-cols))))]))))
+
+;; part 1
+(let [locs (gen-hash-locations 2)]
+  (->> (into #{} (for [[x1 y1 :as a] locs
+                       [x2 y2 :as b] locs
+                       :when (or (not= x1 x2)
+                                 (not= y1 y2))]
+                   (sort [a b])))
+       (map (fn [[[x1 y1] [x2 y2]]]
+              (+ (abs (- x2 x1)) (abs (- y2 y1)))))
+       (reduce +)))
+
+;; part 2
+(let [locs (gen-hash-locations 1000000)]
+  (->> (into #{} (for [[x1 y1 :as a] locs
+                       [x2 y2 :as b] locs
+                       :when (or (not= x1 x2)
+                                 (not= y1 y2))]
+                   (sort [a b])))
+       (map (fn [[[x1 y1] [x2 y2]]]
+              (+ (abs (- x2 x1)) (abs (- y2 y1)))))
+       (reduce +)))