1 files changed, 33 insertions, 0 deletions
diff --git a/03/2.lua b/03/2.lua
new file mode 100644
index 0000000..8c2d155
--- /dev/null
+++ b/03/2.lua
@@ -0,0 +1,33 @@
+#!/usr/bin/env lua
+require("ext")
+local items = {}
+for start, finish in pairs({a = 'z', A = 'Z'}) do
+	for k = start:byte(), finish:byte() do
+		items[string.char(k)] = true
+	end
+end
+
+local groups = {}
+for line in io.lines() do
+	local expanded = {}
+	line:gsub("(%w)",function(w) expanded[w] = true end)
+	table.insert(groups,expanded)
+end
+local common = {}
+for i = 1,#groups,3 do
+	for item, _ in pairs(items) do
+		if groups[i][item] and groups[i + 1][item] and groups[i + 2][item] then
+			table.insert(common, item)
+			break
+		end
+	end
+end
+local sum = 0
+for _, p in pairs(common) do
+	if p >= 'a' and p <= 'z' then
+		sum = sum + (p:byte() - ('a'):byte() + 1)
+	elseif p >= 'A' and p <= 'Z' then
+		sum = sum + (p:byte() - ('A'):byte() + 1) + 26
+	end
+end
+print(sum)