From 55387461c67497e3fca9dd9d675d558745563c14 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Mon, 13 Dec 2021 08:01:32 -0500
Subject: [PATCH] add day 13

---
 day13/part1.clj | 41 +++++++++++++++++++++++++++++++++++++++++
 day13/part2.clj | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 day13/part1.clj
 create mode 100644 day13/part2.clj

diff --git a/day13/part1.clj b/day13/part1.clj
new file mode 100644
index 0000000..bc7bef6
--- /dev/null
+++ b/day13/part1.clj
@@ -0,0 +1,41 @@
+(require '[clojure.string :as str])
+
+(def input (->> (slurp "./in")
+                (str/split-lines)
+                (split-with not-empty)))
+(def points (->> (first input)
+                 (map #(str/split % #","))
+                 (map (partial map read-string))
+                 (set)))
+(def folds (->> (rest (second input))
+                (map #(str/split % #"="))
+                (map #(do [(last (first %)) (read-string (second %))]))))
+
+(loop [fds (take 1 folds) pts points]
+  (if (empty? fds)
+    (println (count pts))
+    (recur
+      (rest fds)
+      (let [ins (first fds) chg (second ins)]
+        (if (= \x (first ins))
+          (reduce
+            #(conj %1
+               (if (< (first %2) chg)
+                 %2
+                 (seq [(- (first %2) (* 2 (- (first %2) chg))) (second %2)])))
+            #{}
+            pts)
+          (reduce
+            #(conj %1
+               (if (< (second %2) chg)
+                 %2
+                 (seq [(first %2) (- (second %2) (* 2 (- (second %2) chg)))])
+                 ))
+            #{}
+            pts)
+          )
+        )
+      )
+    )
+  )
+
diff --git a/day13/part2.clj b/day13/part2.clj
new file mode 100644
index 0000000..89f011d
--- /dev/null
+++ b/day13/part2.clj
@@ -0,0 +1,45 @@
+(require '[clojure.string :as str])
+
+(def input (->> (slurp "./in")
+                (str/split-lines)
+                (split-with not-empty)))
+(def points (->> (first input)
+                 (map #(str/split % #","))
+                 (map (partial map read-string))
+                 (set)))
+(def folds (->> (rest (second input))
+                (map #(str/split % #"="))
+                (map #(do [(last (first %)) (read-string (second %))]))))
+
+(defn print-grid [pts]
+  (doseq [p pts] (println (str/join [(first p) "," (second p)])))
+  )
+
+(loop [fds folds pts points]
+  (if (empty? fds)
+    (print-grid pts)
+    (recur
+      (rest fds)
+      (let [ins (first fds) chg (second ins)]
+        (if (= \x (first ins))
+          (reduce
+            #(conj %1
+               (if (< (first %2) chg)
+                 %2
+                 (seq [(- (first %2) (* 2 (- (first %2) chg))) (second %2)])))
+            #{}
+            pts)
+          (reduce
+            #(conj %1
+               (if (< (second %2) chg)
+                 %2
+                 (seq [(first %2) (- (second %2) (* 2 (- (second %2) chg)))])
+                 ))
+            #{}
+            pts)
+          )
+        )
+      )
+    )
+  )
+