golf

2023/src/day18.clj

@@ -1,28 +1,25 @@
 (ns day18 (:require [core :refer [get-puzzle-input]]
                     [clojure.string :as str]))
 
-(def dir-map {\U [0 -1] \L [-1 0] \R [1 0] \D [0 1]
-              \3 [0 -1] \2 [-1 0] \0 [1 0] \1 [0 1]})
+(def dir-map {\U [-1 0], \L [0 -1], \R [0 1], \D [1 0]})
+(def hex-dir {\0 \R, \1 \D, \2 \L, \3 \U})
 
-(def input
-  (->> (get-puzzle-input 18)
-       (map #(let [[dir n hex-str] (str/split % #" ")]
-               [(dir-map (last dir))
-                (parse-long n)
-                [(dir-map (last (drop-last hex-str)))
-                 (Long/parseLong (subs hex-str 2 (- (count hex-str) 2))
-                                 16)]]))))
+(def input (->> (get-puzzle-input 18)
+                (map #(let [[dir n hex-str] (str/split % #" ")]
+                        [(dir-map (last dir))
+                         (parse-long n)
+                         [(-> hex-str drop-last last hex-dir dir-map)
+                          (-> hex-str
+                              (subs 2 (- (count hex-str) 2))
+                              (Long/parseLong 16))]]))))
 
 ;; Shoelace / Pick's Algorithm, wtf?!
 (defn area [vs]
-  (reduce (fn [[pos ans]
-               [[x y] n]]
-            (let [pos' (+ pos
-                          (* x n))
-                  ans' (+ ans
-                          (* y n pos')
-                          (/ n 2))]
-              [pos' ans']))
+  (reduce (fn [[pos ans] [[row col] n]]
+            (let [pos (+ pos (* col n))]
+              [pos (+ ans
+                      (* row n pos)
+                      (/ n 2))]))
           [0 1]
           vs))