Added Day 4 clojure

diff --git a/04-08-amidakuji/day4.clj b/04-08-amidakuji/day4.clj
new file mode 100644 (file)
index 0000000..3c5d494
--- /dev/null
+++ b/04-08-amidakuji/day4.clj
@@ -0,0 +1,70 @@
+(ns day4
+    (:require [clojure.string :as str]))
+
+(defstruct link :height :left :right)
+
+; (def network (str/split-lines (slurp "../04-small.txt")))
+(def network (str/split-lines (slurp "../04-lines.txt")))
+
+(defn parse-link [l, h]
+    (let [endss (rest (str/split l #"\D+"))
+          ends (map #(Integer/parseInt %) endss)]
+        (struct-map link
+            :height h
+            :left (first ends)
+            :right (second ends))))
+
+(defn parse-network [links]
+    (map-indexed 
+        (fn [i l] (parse-link l i)) 
+        links))
+
+(def parsed-network
+    (parse-network network))
+
+
+(def initial
+    (str/split "abcdefghijklmnopqrstuvwxyz" #""))
+
+(defn apply-link [items link]
+    (let [li (get link :left)
+          ri (get link :right)
+          le (nth items li)
+          re (nth items ri)
+          pre (subvec items 0 li)
+          mid (subvec items (inc li) ri)
+          suf (subvec items (inc ri))]
+    (into [] (concat pre (vector re) mid (vector le) suf))))
+
+(defn follow [items links]
+    (reduce apply-link items links))
+
+
+(defn lane-count [links]
+    (inc (apply max (map (fn [l] (get l :right)) links))))
+
+(defn initial-heights [links]
+    (vec (replicate (lane-count links) -1)))
+
+(defn pack-one [lane-heights link]
+    (let 
+        [li (get link :left)
+         ri (get link :right)
+         new-height (inc (max (nth lane-heights li)
+                              (nth lane-heights ri)))]
+        (assoc lane-heights li new-height ri new-height)))
+
+(defn pack [lane-heights links]
+    (reduce pack-one lane-heights links))
+
+
+(spit "day4.out" (prn-str 
+    (str/join (follow initial parsed-network))))
+
+(spit "day4.out" (prn-str 
+    (apply max 
+        (pack
+            (initial-heights parsed-network)
+            parsed-network)))
+    :append true)
+