1 files changed, 24 insertions, 0 deletions
diff --git a/year2021/day10/part2.clj b/year2021/day10/part2.clj
new file mode 100644
index 0000000..4dfaf3b
--- /dev/null
+++ b/year2021/day10/part2.clj
@@ -0,0 +1,24 @@
+(def to-closing {\{ \} \( \) \[ \] \< \>})
+(def to-score {\) 1 \] 2 \} 3 \> 4})
+
+(defn check-line [input]
+  (loop [in input open '()]
+    (if-let [c (first in)]
+      (when (or (nil? (#{\} \) \] \>} c)) (= (first open) c))
+        (recur
+          (rest in)
+          (if-let [op (to-closing c)]
+            (conj open op)
+            (rest open))))
+      open
+      )))
+
+(->> (slurp "./in")
+     (clojure.string/split-lines)
+     (map (comp check-line vec))
+     (filter some?)
+     (map (partial reduce #(+ (* 5 %1) (to-score %2)) 0))
+     (sort)
+     (#(nth % (quot (count %) 2)))
+     (println))
+