day14: finished part1, part2 wip

2 files changed, 67 insertions, 0 deletions

diff --git a/day14/part1.clj b/day14/part1.clj
new file mode 100644
index 0000000..de03bda
--- /dev/null
+++ b/day14/part1.clj
@@ -0,0 +1,27 @@
+(require '[clojure.string :as str])
+
+(def input (->> (slurp "./in")
+                str/split-lines
+                ((juxt
+                   first
+                   (fn [lines]
+                     (->> lines
+                       (drop 2)
+                       (map #(str/split % #" -> "))
+                       (flatten)
+                       (apply (partial assoc {}))
+                       ))))))
+
+(defn grow-polymer [polymer insertion-rules]
+  (str/join
+    (cons
+      (first polymer)
+      (mapcat (juxt insertion-rules second)
+        (for [i (range 0 (dec (count polymer)))]
+          (subs polymer i (+ i 2)))))))
+
+(def growth-seq (iterate #(grow-polymer % (second input)) (first input)))
+
+(let [freqs (vals (frequencies (nth growth-seq 10)))]
+  (println (- (apply max freqs) (apply min freqs))))
+
diff --git a/day14/part2.clj b/day14/part2.clj
new file mode 100644
index 0000000..4e283ee
--- /dev/null
+++ b/day14/part2.clj
@@ -0,0 +1,40 @@
+(require '[clojure.string :as str])
+(require '[clojure.core.reducers :as r])
+
+(def input (->> (slurp "./in")
+                str/split-lines
+                ((juxt
+                   first
+                   (fn [lines]
+                     (->> lines
+                       (drop 2)
+                       (map #(str/split % #" -> "))
+                       (flatten)
+                       (apply (partial assoc {}))
+                       ))))))
+
+(defn handle-pair [pair steps]
+  (if (= 0 steps)
+    (frequencies (rest pair))
+    (let [ins ((second input) pair)
+          p1  (handle-pair (str/join [(first pair) ins]) (dec steps))
+          p2  (handle-pair (str/join [ins (second pair)]) (dec steps))]
+      (reduce
+        (fn [r p] (update r (key p) #(if (nil? %) (val p) (+ (val p) %))))
+        p1 p2)
+      )))
+
+(println
+  (reduce
+    (fn [tot pair]
+      (let [freqs (handle-pair pair 23)]
+        (println "Finished pair " pair)
+        (reduce
+          (fn [r p] (update r (key p) #(if (nil? %) (val p) (+ (val p) %))))
+          tot
+          freqs)))
+    {}
+    (for [i (range 0 (dec (count (first input))))]
+      (subs (first input) i (+ i 2)))
+    ))
+