1 files changed, 30 insertions, 0 deletions
diff --git a/year2021/day15/part1.clj b/year2021/day15/part1.clj
new file mode 100644
index 0000000..7838e34
--- /dev/null
+++ b/year2021/day15/part1.clj
@@ -0,0 +1,30 @@
+(def input (->> (slurp "./in")
+                (clojure.string/split-lines)
+                (mapv (partial mapv (comp read-string str)))
+                (#(for [y (range 0 (count %)) x (range 0 (count (first %)))]
+                    {[y x] (get-in % [y x])}))
+                (into {})))
+
+(def dim (apply max (map first (keys input))))
+
+(defn find-neighbors [u]
+  (filter #(contains? input %) [(update u 0 inc)
+                                (update u 0 dec)
+                                (update u 1 inc)
+                                (update u 1 dec)]))
+
+(loop [dist (zipmap (keys input) (repeat ##Inf))
+       Q    {[0 0] 0}]
+  (if (empty? Q)
+    (println (dist [dim dim]))
+    (let [[u distu] (first Q)
+          NN (reduce
+               #(let [dv (+ distu (input %2))]
+                  (cond-> %1
+                    (> ((first %1) %2) dv)
+                    (-> (update 0 assoc %2 dv)
+                        (update 1 assoc %2 dv))))
+               [dist {}]
+               (find-neighbors u))]
+      (recur (first NN) (sort-by val < (into (rest Q) (second NN)))))))
+