day 21 part 1

day21/part1.lua

@@ -0,0 +1,26 @@
+#!/usr/bin/env luajit
+require("utils")
+
+local f = io.open(arg[3])
+local fst = string.match(f:read("*l"), "Player 1 starting position: (.*)")
+local snd = string.match(f:read("*l"), "Player 2 starting position: (.*)")
+f:close()
+
+function rolls()
+	local i = 0
+	return function()
+		i = i + 1
+		return i
+	end
+end
+
+local r = rolls()
+local turn = 0
+local fstscore, sndscore = 0, 0
+repeat
+	snd, fst = (fst + r() + r() + r() - 1) % 10 + 1, snd
+	sndscore, fstscore = fstscore + snd, sndscore
+	turn = turn + 3
+until sndscore >= 1000
+
+print(fstscore, turn, fstscore * turn)