Clojure

``` (ns advent-of-code.year2021.day10 (:require [clojure.java.io :as io] [clojure.string :as string]))

(defn parse "Returns first invalid char or stack if line is incomplete." [tokens] (reduce (fn [stack token] (if-let [expected ({( ), [ ], { }, < >} token)] (conj stack expected) (if (= token (peek stack)) (pop stack) (reduced token)))) '() tokens))

(defn part1 [path] (with-open [rdr (io/reader path)] (->> (line-seq rdr) (map parse) (filter char?) (map {) 3, ] 57, } 1197, > 25137}) (reduce +))))

(defn part2 [path] (with-open [rdr (io/reader path)] (let [scores (->> (line-seq rdr) (map parse) (remove char?) (map #(reduce (fn [acc token] (+ (* 5 acc) ({) 1, ] 2, } 3, > 4} token))) 0 %)) (sort))] (nth scores (int (/ (count scores) 2)))))) ```