day 10 WIP

src/day10.clj

@@ -0,0 +1,47 @@
+(ns day10
+  (:require [mapped-area]
+            [helpers :refer [get-input]]))
+
+(def test-map
+  (mapped-area/parse-elements
+   (mapped-area/read-mapped-area
+"89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732")))
+
+(defn trailheads [a]
+  (reduce
+   (fn [coll [coord value]]
+     (if (= value 0)
+       (conj coll coord)
+       coll))
+   []
+   (mapped-area/mapped-area-indexed-seq a)))
+
+(defn step [a [x y]]
+  (let [c (get-in a [x y])
+        even-gradual-uphill?
+        (fn [[x' y']]
+          (let [c' (get-in a [x' y'])]
+            (= 1 (- c' c))))]
+      (->>
+       [[(inc x) y] [(dec x) y]
+        [x (inc y)] [x (dec y)]]
+       (filter (partial mapped-area/mapped? a))
+       (filter even-gradual-uphill?))))
+
+(defn walk [a trailhead]
+  (loop [positions [trailhead]]
+    (println positions)
+    (if (== 9 (get-in a (first positions)))
+      (count positions)
+      (recur (mapcat (partial step a) (set positions))))))
+
+
+(reduce +
+        (map (partial walk test-map) (trailheads test-map)))

src/mapped_area.clj

@@ -67,12 +67,33 @@ ijkl")
         (< x (w a))
         (< y (h a)))))
 
-(test #'read-mapped-area)
-(test #'h)
-(test #'w)
-(test #'mapped?)
-
 (defn mapped-area-indexed-seq [a]
   (for [x (range (w a))
         y (range (h a))]
     (vector [x y] (get-in a [x y]))))
+
+(def test-map-num
+"1234
+5678")
+
+(defn parse-elements
+  {:test
+   #(do
+      (let [a (parse-elements
+               (read-mapped-area test-map-num))]
+        (assert (number? (get-in a [0 0])))
+        (assert (== 5 (get-in a [0 0])))
+        (assert (== 1 (get-in a [0 1])))))}
+  ([a] (parse-elements a (comp parse-long str)))
+  ([a parse-fn]
+   (reduce
+    (fn [coll [coord value]]
+      (assoc-in coll coord (parse-fn value)))
+    [[]]
+    (mapped-area-indexed-seq a))))
+
+(test #'read-mapped-area)
+(test #'h)
+(test #'w)
+(test #'mapped?)
+(test #'parse-elements)