Day5 Second puzzle

2025/'

@@ -0,0 +1,2 @@
+-- Using Autorun now
+print("Starting Day 5...")

2025/Day5/Day5.lua

@@ -2,10 +2,17 @@
 print("Starting Day 5...")
 
 local input_file = "Day5/full"
+local DEBUG = false
 local Freshness = {
 	Range = {},
 }
 
+function debug(msg)
+	if DEBUG then
+		print(msg)
+	end
+end
+
 function Freshness.add(R)
 	local S, E = string.match(R, "(%d+)-(%d+)")
 	local Set = { tonumber(S), tonumber(E) }
@@ -28,6 +35,47 @@ function Freshness.check(value)
 	return false
 end
 
+function Freshness.CalculateIDs()
+	-- Copy and Sort
+	table.sort(Freshness.Range, function(a, b)
+		return a[1] < b[1]
+	end)
+	local IDTable = {}
+	local count = 0
+	for kadd, vadd in pairs(Freshness.Range) do
+		local merged = false
+		debug("Checking " .. vadd[1] .. "-" .. vadd[2])
+		for kcheck, vcheck in pairs(IDTable) do
+			-- Check Lower
+			debug("  Compare " .. vcheck[1] .. "-" .. vcheck[2])
+			if vadd[1] >= vcheck[1] and vadd[1] <= vcheck[2] then
+				if vadd[2] > vcheck[2] then
+					debug("  Lower number inside range and higher number higher")
+					IDTable[kcheck][2] = vadd[2]
+				end
+				merged = true
+			end
+			-- Check higher
+			if vadd[2] >= vcheck[1] and vadd[2] <= vcheck[2] then
+				if vadd[1] < vcheck[1] then
+					debug("  Higher number inside range and lower number lower")
+					IDTable[kcheck][1] = vadd[1]
+				end
+				merged = true
+			end
+		end
+		if not merged then
+			table.insert(IDTable, vadd)
+		end
+	end
+	local countIDs = 0
+	for k, v in pairs(IDTable) do
+		countIDs = countIDs + (v[2] - v[1]) + 1
+		print(string.format("Range %d-%d = %d  Total %d", v[1], v[2], (v[2] - v[1] + 1), countIDs))
+	end
+	return countIDs
+end
+
 local InputMode = true
 local FreshCounter = 0
 for line in io.lines(input_file) do
@@ -37,10 +85,10 @@ for line in io.lines(input_file) do
 		Freshness.add(line)
 	else
 		if Freshness.check(line) then
-			print("Fresh Item " .. line)
 			FreshCounter = FreshCounter + 1
 		end
 	end
 end
 
 print("Found Fresh Ingredients " .. FreshCounter)
+print(string.format("Found IDs %18.0f", Freshness.CalculateIDs()))

2025/README.md

@@ -23,3 +23,11 @@ This is mostly so I can keep notes on my progress, in single markdown format so
 ## Lessons fourth day
 
 1. Need about an hour to do both, but also speeding up
+
+## Lessons fifth day
+
+1. Lua has a maximum table size, so no brute forcing :)
+2. When doing any type of comparing, a good pre-sort helps 
+
+
+