From 3555be54c2abb8d5ece008a60dbdfbde0ffbddd7 Mon Sep 17 00:00:00 2001
From: Alex Pickering <alex@cogarr.net>
Date: Fri, 7 Feb 2025 12:49:48 -0600
Subject: inital commit

---
 07/2.lua | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 07/2.lua

(limited to '07/2.lua')

diff --git a/07/2.lua b/07/2.lua
new file mode 100644
index 0000000..93c90df
--- /dev/null
+++ b/07/2.lua
@@ -0,0 +1,57 @@
+local ds = {} -- unique value
+local pwd, tree, output = {}, {[ds]=0}, error
+local allfolders = {tree}
+local function walk(dir, path, f)
+	local cursor = dir
+	for _,v in ipairs(path) do
+		f(cursor)
+		cursor = cursor[v]
+	end
+	f(cursor)
+	return cursor
+end
+local commands = {}
+function commands.cd(arg)
+	if arg == "/" then pwd = {}
+	elseif arg == ".." then table.remove(pwd)
+	else table.insert(pwd, arg) end
+end
+function commands.ls()
+	local cursor = walk(tree, pwd, function() end)
+	output = function(line)
+		if line:match("^dir") then
+			local dirname = line:match("^dir (%w+)$")
+			cursor[dirname] = {[ds]=0}
+			table.insert(allfolders,cursor[dirname])
+		else
+			local filesize, filename = line:match("(%d+) ([%w.]+)")
+			walk(
+				tree,
+				pwd,
+				function(f) f[ds] = f[ds] + tonumber(filesize) end
+			)[filename] = filesize
+		end
+	end
+
+end
+for line in io.lines() do
+	if line:match("^%$") then
+		local line_split = {}
+		for chunk in line:gmatch("(%S+)") do
+			table.insert(line_split,chunk)
+		end
+		table.remove(line_split,1) -- remove '$'
+		-- remove command before calling it
+		commands[table.remove(line_split,1)](table.unpack(line_split))
+	else
+		output(line)
+	end
+end
+local needs = 3e7 - (7e7 - tree[ds])
+table.sort(allfolders,function(a,b) return a[ds] < b[ds] end )
+for i = 1,#allfolders do
+	if allfolders[i][ds] > needs then
+		print(allfolders[i][ds])
+		break
+	end
+end
-- 
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