Day 11 - UGLY AF

day11/part2.py

@@ -0,0 +1,50 @@
+import numpy as np
+from day11.common import char_to_int
+
+lines = np.array([[char_to_int(x) for x in line.strip()] for line in open("input.txt")], dtype=np.byte)
+shape = lines.shape
+
+RAYS = [(-1, -1), (0, -1), (1, -1), (-1, 0), (1, 0), (-1, 1), (0, 1), (1, 1)]
+
+last = -1
+while True:
+    curr = np.count_nonzero(lines == 1)
+    if curr == last:
+        print(last)
+        break
+    last = curr
+
+    new = np.zeros_like(lines, dtype=np.byte)
+    for idx, val in np.ndenumerate(lines):
+        if val == 0:
+            continue
+        if val == -1:
+            found = False
+            for ray in RAYS:
+                ray = np.array(ray)
+                pos = np.array(idx) + ray
+                while 0 <= pos[0] < shape[0] and 0 <= pos[1] < shape[1]:
+                    if lines[tuple(pos)] == 1:
+                        found = True
+                        break
+                    elif lines[tuple(pos)] == -1:
+                        break
+                    pos = pos + ray
+                if found:
+                    break
+            new[idx] = 1 if not found else -1
+            continue
+        if val == 1:
+            found = 0
+            for ray in RAYS:
+                ray = np.array(ray)
+                pos = np.array(idx) - ray
+                while 0 <= pos[0] < shape[0] and 0 <= pos[1] < shape[1]:
+                    if lines[tuple(pos)] == 1:
+                        found += 1
+                        break
+                    elif lines[tuple(pos)] == -1:
+                        break
+                    pos = pos - ray
+            new[idx] = -1 if found >= 5 else 1
+    lines = new