Day 1: Part 1

day1/day1.lua

@@ -0,0 +1,44 @@
+--Lua 5.4.2
+local File = io.open("input.txt", "r")
+
+if not File then
+    print("File not found")
+    return
+end
+
+local LeftList = {}
+local RightList = {}
+local Distances = {}
+
+for Line in File:lines() do
+    local LeftId, RightId = Line:match("(%d+)%s+(%d+)")
+    table.insert(LeftList, tonumber(LeftId))
+    table.insert(RightList, tonumber(RightId))
+end
+
+local function SortFunction(a, b)
+    return a < b
+end
+
+table.sort(LeftList, SortFunction)
+table.sort(RightList, SortFunction)
+
+if #LeftList ~= #RightList then
+    print("Lists are not the same size")
+    return
+end
+
+for ListIndex = 1, #LeftList do
+    local LeftId, RightId = LeftList[ListIndex], RightList[ListIndex]
+    local Distance = math.abs(LeftId - RightId)
+    Distances[ListIndex] = Distance
+end
+
+local TotalDistance = 0
+for _, Distance in next, Distances do
+    TotalDistance = TotalDistance + Distance
+end
+
+print("Total distance:", TotalDistance)
+
+File:close()