day 6

day06/part1.lua

@@ -0,0 +1,30 @@
+#!/usr/bin/env luajit
+require("utils")
+
+local fishes = {}
+for timer = 0, 9 do
+	fishes[timer] = 0
+end
+
+for _, timer in pairs(split(io.open(arg[3]):read("*a"), ",")) do
+	fishes[tonumber(timer)] = fishes[tonumber(timer)] + 1
+end
+
+for day = 1, 256 do
+	fishes[9] = (fishes[0] or 0) + (fishes[9] or 0)
+	fishes[7] = (fishes[0] or 0) + (fishes[7] or 0)
+	for timer = 0, 9 do
+		fishes[timer] = fishes[timer + 1]
+	end
+	for k = 0, 9 do
+		io.write((fishes[k] or "_")..",")
+	end
+	io.write("\n")
+end
+
+local sum = 0
+for timer, fishday in pairs(fishes) do
+	sum = sum + fishday
+end
+
+print(sum)