From d1bb4af495094eec997cbe7e99a382877c7c7b5a Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Tue, 14 Dec 2021 22:04:10 -0500
Subject: checking out 2020
---
year2020/day1/part2.clj | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
create mode 100644 year2020/day1/part2.clj
(limited to 'year2020/day1/part2.clj')
diff --git a/year2020/day1/part2.clj b/year2020/day1/part2.clj
new file mode 100644
index 0000000..0b6ef9d
--- /dev/null
+++ b/year2020/day1/part2.clj
@@ -0,0 +1,20 @@
+(require 'clojure.set)
+
+(defn find-sum [sum lst]
+ (->> lst
+ ((juxt set (comp set #(map (partial - sum) %))))
+ (apply clojure.set/intersection)
+ (vec)))
+
+(->> (slurp "./in")
+ clojure.string/split-lines
+ ((comp set (partial map read-string)))
+ ((fn [lst]
+ (reduce
+ #(let [fnd (find-sum (- 2020 %2) (clojure.set/difference lst #{%2}))]
+ (if (empty? fnd) %1 [%2 fnd]))
+ []
+ lst)))
+ flatten
+ (apply *)
+ (println))
--
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