inital commitHEADmaster

1 files changed, 74 insertions, 0 deletions

diff --git a/25/1.lua b/25/1.lua
new file mode 100644
index 0000000..53d8794
--- /dev/null
+++ b/25/1.lua
@@ -0,0 +1,74 @@
+require "ext"
+
+local snafu = {
+	["0"] = 0,
+	["1"] = 1,
+	["2"] = 2,
+	["-"] = -1,
+	["="] = -2,
+}
+local snafu_rev = {}
+for k,v in pairs(snafu) do
+	snafu_rev[v] = k
+end
+
+local function decode(s)
+	local t = {}
+	for c in s:gmatch("(.)") do
+		table.insert(t,c)
+	end
+	local cursor = 1
+	local n = 0
+	while #t > 0 do
+		local val = table.remove(t)
+		n = n + (snafu[val] * cursor)
+		cursor = cursor * 5
+	end
+	return n
+end
+
+-- 4 8 9 0
+local function encode(n,location)
+	--print("Encoding",n)
+	if snafu_rev[n] then
+		--print("Snafu of",n,"is",snafu_rev[n])
+		return snafu_rev[n]
+	end
+	local rem = n % 5
+	if rem == 0 or rem == 1 or rem == 2 then
+		return encode(math.floor(n/5)) .. snafu_rev[rem]
+	elseif rem == 3 or rem == 4 then
+		return encode(math.floor(n/5)+1) .. snafu_rev[rem - 5]
+	end
+	
+end
+
+local sum = 0
+for line in io.lines() do
+	sum = sum + decode(line)
+end
+print(encode(sum))
+--[[
+print(encode(6))
+local encodings = {
+	[1]="1",
+	[2]="2",
+	[3]="1=",
+	[4]="1-",
+	[5]="10",
+	[6]="11",
+	[7]="12",
+	[8]="2=",
+	[9]="2-",
+	[10]="20",
+	[15]="1=0",
+	[20]="1-0",
+	[2022]="1=11-2",
+	[12345]="1-0---0",
+	[314159265]="1121-1110-1=0",
+}
+for k,v in pairs(encodings) do
+	local fe = encode(k)
+	print("Finished encoding of",k,"is",fe)
+	assert(fe == v)
+end]]