day 17

Author: r0f1

README.md

@@ -18,7 +18,7 @@
 |[14](https://adventofcode.com/2020/day/14)|Docking Data|[py](/day14/main.py)|
 |[15](https://adventofcode.com/2020/day/15)|Rambunctious Recitation|[py](/day15/main.py), [alt](/day15/alt.py)|
 |[16](https://adventofcode.com/2020/day/16)|Ticket Translation|[py](/day16/main.py), [alt](/day16/alt.py)|
-|[17](https://adventofcode.com/2020/day/17)|-|-|
+|[17](https://adventofcode.com/2020/day/17)|Conway Cubes|[py](/day17/main.py)|
 |[18](https://adventofcode.com/2020/day/18)|-|-|
 |[19](https://adventofcode.com/2020/day/19)|-|-|
 |[20](https://adventofcode.com/2020/day/20)|-|-|

day17/main.py

@@ -0,0 +1,24 @@
+import numpy as np
+from scipy.ndimage import generic_filter
+
+with open("input.txt") as f:
+    lines = [list(x.strip()) for x in f]
+
+def f(x):
+    if x[len(x) // 2] == 0:
+        if np.sum(x) == 3: return 1
+        else: return 0
+    else:
+        if np.sum(x) in (3,4): return 1
+        else: return 0
+
+d = 20
+for dims in [3,4]:
+    a = (np.array(lines) == "#").astype(np.uint8)
+    for _ in range(dims-2):
+        a = np.reshape(a, (1,)+a.shape)
+    arr = np.pad(a, (d-a.shape[0]) // 2)
+    kernel = np.ones([3]*dims, dtype=np.uint8)
+    for i in range(6):
+        arr = generic_filter(arr, f, footprint=kernel, mode="constant", cval=0)
+    print(np.sum(arr))