From: Jack Kinsey <j.jameskinsey@gmail.com>
Date: Fri, 2 Dec 2022 19:19:01 +0000 (-0500)
Subject: Day 2
X-Git-Url: http://git.jkinsey.net/?a=commitdiff_plain;h=a81450cc168a13a7fc134328009271544bb1fa3b;p=adventofcode2022.git

Day 2
---

diff --git a/src/day02.fnl b/src/day02.fnl
new file mode 100644
index 0000000..a7b0561
--- /dev/null
+++ b/src/day02.fnl
@@ -0,0 +1,88 @@
+(module net.journcy.aoc2022.day02)
+
+(defn inc [n] (+ n 1))
+(defn dec [n] (- n 1))
+(defn lines [file] (icollect [v (io.lines file)] v))
+(defn numbers [file] (icollect [v (io.lines file)] (tonumber v)))
+(defn head [tbl] (. tbl 1))
+(defn last [tbl] (let [n (# tbl)] (. tbl n)))
+(defn map [f tbl] (icollect [_ v (ipairs tbl)] (f v)))
+(defn add [a b] (+ a b))
+(defn gt [a b] (> a b))
+(defn accnum [f tbl] 
+  (accumulate [acc 0
+               _ v (ipairs tbl)]
+    (f acc v)))
+(defn take [n tbl]
+  (accumulate [t []
+               i v (ipairs tbl)
+               &until (> i n)]
+    (doto t (table.insert v))))
+(defn partition [tbl brk]
+  (accumulate [parts [[]]
+               _ v (ipairs tbl)]
+    (do 
+      (if (= v brk)
+        (table.insert parts [])
+        (table.insert (last parts) v))
+      parts)))
+(defn sum [tbl] (accnum add tbl))
+(defn sort [tbl f] (do (table.sort tbl f) tbl))
+
+; A: rock, B: paper, C: scissors
+; X: rock, Y: paper, Z: scissors
+(defn determine [play resp]
+  (match [play resp]
+    [:A :X] 3
+    [:A :Y] 6
+    [:A :Z] 0
+    [:B :X] 0
+    [:B :Y] 3
+    [:B :Z] 6
+    [:C :X] 6
+    [:C :Y] 0
+    [:C :Z] 3))
+
+(defn permute [sym dir]
+  (match [sym dir]
+    [:A :X] :C
+    [:B :X] :A
+    [:C :X] :B
+    [ S :Y]  S
+    [:A :Z] :B
+    [:B :Z] :C
+    [:C :Z] :A))
+
+(defn score [round]
+  (let [play (string.sub round 1 1)
+        resp (string.sub round 3 3)
+        outcome (determine play resp)]
+    (+ outcome
+       (match resp :X 1 :Y 2 :Z 3))))
+
+(defn nuscore [round]
+  (let [play (string.sub round 1 1)
+        resp (string.sub round 3 3)]
+    (+ (match resp :X 0 :Y 3 :Z 6)
+       (match (permute play resp)
+         :A 1 :B 2 :C 3))))
+
+(comment
+  (score "A Y")
+  (score "B X")
+  (score "C Z")
+  (map score (take 1 (lines "input/day02.txt"))))
+
+(defn part1 [lines]
+  (->> lines
+       (map score)
+       sum))
+
+(defn part2 [lines]
+  (->> lines
+       (map nuscore)
+       sum))
+
+(comment
+  (part1 (lines "input/day02.txt"))
+  (part2 (lines "input/day02.txt")))