Day 11

day11/input.txt

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+6636827465
+6774248431
+4227386366
+7447452613
+6223122545
+2814388766
+6615551144
+4836235836
+5334783256
+4128344843

day11/part1.py

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+#!/usr/bin/env python3
+
+import numpy as np
+from scipy.signal import convolve2d
+
+arr = np.array([[int(n) for n in line.strip()] for line in open("input.txt")])
+flashes = 0
+
+for step in range(100):
+    arr = arr + 1
+    next_arr = arr
+    mask = np.zeros_like(arr)
+    changes = 0
+    while True:
+        mask[next_arr >= 10] = 1
+        next_arr = arr + convolve2d(mask, np.array([[1, 1, 1], [1, 0, 1], [1, 1, 1]]), boundary='fill', mode='same')
+        if changes == (changes := np.sum(mask)):
+            arr = next_arr
+            arr[arr >= 10] = 0
+            flashes += np.sum(mask)
+            break
+
+print(flashes)
+

day11/part2.py

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+#!/usr/bin/env python3
+from functools import reduce
+
+import numpy as np
+from scipy.signal import convolve2d
+
+arr = np.array([[int(n) for n in line.strip()] for line in open("input.txt")])
+
+for step in range(1000):
+    arr = arr + 1
+    next_arr = arr
+    mask = np.zeros_like(arr)
+    changes = 0
+    while True:
+        mask[next_arr >= 10] = 1
+        next_arr = arr + convolve2d(mask, np.array([[1, 1, 1], [1, 0, 1], [1, 1, 1]]), boundary='fill', mode='same')
+        if changes == (changes := np.sum(mask)):
+            arr = next_arr
+            arr[arr >= 10] = 0
+            if np.sum(mask) == reduce(lambda a, b: a*b, arr.shape):
+                print(step + 1)
+                exit(0)
+            break
+