day 1

.gitignore

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+# ---> Clojure
+pom.xml
+pom.xml.asc
+*.jar
+*.class
+/lib/
+/classes/
+/target/
+/checkouts/
+.lein-deps-sum
+.lein-repl-history
+.lein-plugins/
+.lein-failures
+.nrepl-port
+.cpcache/
+

deps.edn

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+{:paths ["src" "inputs"]
+ :deps {org.clojure/clojure {:mvn/version "1.12.0"}}}

inputs/day1.example

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+3   4
+4   3
+2   5
+1   3
+3   9
+3   3

src/day1.clj

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+(ns day1
+  (:require [clojure.edn :as edn]
+            [clojure.string :as s]))
+
+
+(def input
+  (->> (slurp "inputs/day1")
+       s/split-lines
+       (map #(s/split % #"\ +"))
+       (map #(map edn/read-string %))))
+
+(def left-list (map first input))
+(def right-list (map second input))
+
+(def distances
+  (map (fn [l r] (abs (- r l)))
+       (sort left-list)
+       (sort right-list)))
+
+(defn count-n-in-right-list [n]
+  (count (filter #(= n %) right-list)))
+
+(defn similarity-for-n [n]
+  (* n (count-n-in-right-list n)))
+
+
+(println "Total distance:" (reduce + distances))
+(println "Similarity score:" (reduce + (map similarity-for-n left-list)))