From 0df6aa12fd433f7fefc5302f712c3060615cda0f Mon Sep 17 00:00:00 2001
From: Marcin Chrzanowski <marcin.j.chrzanowski@gmail.com>
Date: Fri, 25 Dec 2020 15:49:44 +0100
Subject: Add day 22

---
 22/a.lua | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 22/a.lua

(limited to '22/a.lua')

diff --git a/22/a.lua b/22/a.lua
new file mode 100644
index 0000000..50cd196
--- /dev/null
+++ b/22/a.lua
@@ -0,0 +1,40 @@
+deck1 = {}
+file = io.open('input.txt')
+for line in file:lines() do
+    if line:find('%d+') then
+        table.insert(deck1, tonumber(line))
+    elseif line == '' then
+        break
+    end
+end
+deck2 = {}
+for line in file:lines() do
+    if line:find('%d+') then
+        table.insert(deck2, tonumber(line))
+    end
+end
+
+ended = false
+
+while #deck1 > 0 and #deck2 > 0 do
+    card1 = table.remove(deck1, 1)
+    card2 = table.remove(deck2, 1)
+    if card1 > card2 then
+        table.insert(deck1, card1)
+        table.insert(deck1, card2)
+    else
+        table.insert(deck2, card2)
+        table.insert(deck2, card1)
+    end
+end
+
+deck = deck1
+if #deck1 == 0 then
+    deck = deck2
+end
+
+score = 0
+for i = 1, #deck do
+    score = score + i * (deck[#deck - i + 1]) 
+end
+print(score)
-- 
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