1 files changed, 56 insertions(+), 30 deletions(-)

M 2023/14.lua

@@ 1,4 1,5 @@
 local grid, R, C, E = {}, string.byte('O#.', 1, 3)
+io.input(arg[1])
 for line in io.lines() do
 	table.insert(grid, {string.byte(line, 1, #line)})
 end


@@ 22,46 23,71 @@ local function load()
 	return l
 end
 
-local function tilt(coord)
-	local cubes = {}
-	for i = 1, #grid do
-		cubes[i] = 0
-	end
-	for j = 1, #grid do
-		for i = 1, #grid do
-			local x, y = coord(i, j)
-			local c = grid[y][x]
+local i, cycles, seen, cubes, last, ans1 = 1, 1000000000, {}, {}
+local size = #grid
+local cubes = {}
+while i <= cycles do
+	for x = 1, size do cubes[x] = 0 end
+	for y = 1, size do
+		local row = grid[y]
+		for x = 1, size do
+			local c = row[x]
 			if c == C then
-				cubes[i] = j
+				cubes[x] = y
 			elseif c == R then
-				grid[y][x] = E
-				local j = cubes[i] + 1
-				cubes[i] = j
-				x, y = coord(i, j)
+				row[x] = E
+				local y = cubes[x] + 1
+				cubes[x] = y
 				grid[y][x] = c
 			end
 		end
 	end
-end
-
-local function north(i, j) return i, j end
-local function west(i, j) return j, i end
-local function south(i, j) return i, #grid - j + 1 end
-local function east(i, j) return #grid - j + 1, i end
-
-local i, cycles, seen, cubes, last, ans1 = 1, 1000000000, {}, {}
-while i <= cycles do
-	tilt(north)
 	if i == 1 then ans1 = load() end
-	tilt(west)
-	tilt(south)
-	tilt(east)
+	for y = 1, size do
+		local row, cube = grid[y], 0
+		for x = 1, size do
+			local c = row[x]
+			if c == C then
+				cube = x
+			elseif c == R then
+				row[x] = E
+				cube = cube + 1
+				row[cube] = c
+			end
+		end
+	end
+	for x = 1, size do cubes[x] = size + 1 end
+	for y = size, 1, -1 do
+		local row = grid[y]
+		for x = 1, size do
+			local c = row[x]
+			if c == C then
+				cubes[x] = y
+			elseif c == R then
+				row[x] = E
+				local y = cubes[x] - 1
+				cubes[x] = y
+				grid[y][x] = c
+			end
+		end
+	end
+	for y = 1, size do
+		local row, cube = grid[y], size + 1
+		for x = size, 1, -1 do
+			local c = row[x]
+			if c == C then
+				cube = x
+			elseif c == R then
+				row[x] = E
+				cube = cube - 1
+				grid[y][cube] = c
+			end
+		end
+	end
 	if not last then
 		local k = key()
 		last = seen[k]
-		if last then
-			cycles = (cycles - last) % (i - last) + i
-		end
+		if last then cycles = (cycles - last) % (i - last) + i end
 		seen[k] = i
 	end
 	i = i + 1