Solve day03

1 files changed, 55 insertions, 0 deletions

diff --git a/src/aoc_2022/day03.clj b/src/aoc_2022/day03.clj
new file mode 100644
index 0000000..38ae011
--- /dev/null
+++ b/src/aoc_2022/day03.clj
@@ -0,0 +1,55 @@
+(ns aoc-2022.day03)
+(require '[clojure.java.io :as io])
+(require '[aoc-2022.utils :as utils])
+
+(defn compartments [sack]
+  (let [n (count sack)]
+    [(take (/ n 2) sack)
+     (drop (/ n 2) sack)]))
+
+(defn find-common [needles haystack]
+  (let [needle (first needles)
+        occurs (fn [hs] (filter #(= needle %) hs))]
+    (cond
+      (nil? needle) nil
+      (not (empty? (occurs haystack))) needle
+      :else (find-common (rest needles) haystack))))
+
+(defn priority-of [item]
+  (cond
+    (<= (int item) (int \Z)) (+ 27 (- (int item) (int \A)))
+    :else (+ 1 (- (int item) (int \a)))))
+
+(defn task1 [rows]
+  (->> rows
+       (map compartments)
+       (map (fn [[c1 c2]] (find-common c1 c2)))
+       (map priority-of)
+       (reduce +)
+       ))
+
+(defn find-common2 [needles hs1 hs2]
+  (let [needle (first needles)
+        occurs (fn [hs] (filter #(= needle %) hs))]
+    (cond
+      (nil? needle)
+          nil
+      (and
+       (not (empty? (occurs hs1)))
+       (not (empty? (occurs hs2))))
+          needle
+      :else
+          (find-common2 (rest needles) hs1 hs2))))
+
+(defn task2 [rows]
+  (->> rows
+       (partition 3)
+       (map (fn [[c1 c2 c3]] (find-common2 c1 c2 c3)))
+       (map priority-of)
+       (reduce +)))
+
+(with-open [rdr (io/reader "resources/day03_actual.txt")]
+  (let [rows (line-seq rdr)]
+    (do
+      (println "task1:" (task1 rows))
+      (println "task2:" (task2 rows)))))