o-o

2020/17/17.py

@@ -0,0 +1,36 @@
+def main(d):
+	# create a set of tuples 
+	seed = open('input.txt').read().split('\n')
+	state = set(
+		(d - 2) * (0,) + (i, j) # zero-pad coords
+		for i, row in enumerate(seed)
+		for j, cell in enumerate(row)
+		if cell == '#'
+	)
+
+	# generate all tuples -1..1 in all dimensions
+	neighbors = [()] # list contains empty tuple which will be iterated over
+	for _ in range(d):
+		neighbors = [
+			t + (x,)
+			for x in [-1, 0, 1]
+			for t in neighbors
+		]
+	neighbors.remove(d * (0,)) # this is the center cell
+
+	# do 6 iterations according to rules
+	from collections import Counter
+	for _ in range(6):
+		state = set(
+			t
+			for t, count in Counter( # unpack the tuple and its count of neighboring active cells
+				tuple(map(sum, zip(t, n))) # add neighbors kernel to each active cell
+				for t in state
+				for n in neighbors
+			).items()
+			if count == 3 or t in state and count == 2
+		)
+
+	return len(state)
+
+print(main(3), main(4))

2020/17/input.txt

@@ -0,0 +1,8 @@
+......##
+####.#..
+.##....#
+.##.#..#
+........
+.#.#.###
+#.##....
+####.#..