From 8afe06a504283d2408f1fe5cdd684e56d0fa945f Mon Sep 17 00:00:00 2001
From: Leah Neukirchen <leah@vuxu.org>
Date: Fri, 18 Dec 2020 12:12:32 +0100
Subject: day16

---
 day16.clj | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 day16.clj

(limited to 'day16.clj')

diff --git a/day16.clj b/day16.clj
new file mode 100644
index 0000000..fce1aa3
--- /dev/null
+++ b/day16.clj
@@ -0,0 +1,63 @@
+(let [data (slurp "day16")
+      [a b c] (clojure.string/split data #"\n\n")]
+  (def ranges a)
+  (def mine b)
+  (def nearby c))
+
+(def line-ranges
+  (->> ranges
+       clojure.string/split-lines
+       (map (fn [line]
+              (->> line
+                   (re-seq #"(\d+)-(\d+)")
+                   (map (fn [[_ f t]]
+                          (range (Integer/parseInt f)
+                                 (inc (Integer/parseInt t)))))
+                   flatten)))))
+
+(def all-in-ranges
+  (->> line-ranges
+       flatten
+       set))
+
+(def nearby-tickets
+  (->> nearby
+       clojure.string/split-lines
+       rest
+       (map (fn [s] (clojure.string/split s #",")))
+       (map (partial map #(Integer/parseInt %)))))
+
+(reduce + (remove all-in-range (flatten nearby-tickets))) ; => 24021
+
+(def my-ticket
+  (->> mine
+       clojure.string/split-lines
+       second
+       (#(clojure.string/split % #","))
+       (map #(Integer/parseInt %))
+       vec))
+
+(def valid-tickets
+  (->> nearby-tickets
+       (filter (fn [t] (empty? (remove all-in-range t) )))))
+
+(defn valid-positions [line-range]
+  (let [s (set line-range)]
+    (filter (fn [i]
+              (every? (fn [ticket]
+                        (s (nth ticket i)))
+                      valid-tickets))
+            (range (count line-ranges)))))
+
+(->> line-ranges
+     (map valid-positions)
+     (sort-by count)
+     (cons ())
+     (partition 2 1) 
+     (map (fn [[x y]] (first (remove (set x) y))))
+    
+     (drop 6)  ;; ???
+     (take 6)
+
+     (map my-ticket)
+     (apply *)) ; => 1289178686687
-- 
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