Day 09

day09/part2.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+import operator
+from functools import reduce
+import numpy as np
+from skimage.segmentation import flood_fill
+
+
+arr = np.array([[int(n) for n in line.strip()] for line in open("input.txt")])
+
+borders = np.zeros_like(arr)
+borders[arr == 9] = 1
+curr_sum = np.sum(borders)
+areas = []
+while np.shape(nxt := np.array(np.where(borders == 0))) != (2, 0):
+    borders = flood_fill(borders, tuple(nxt[:, 0]), 1, tolerance=0, connectivity=1)
+    areas.append(-curr_sum + (curr_sum := np.sum(borders)))
+print(reduce(operator.mul, sorted(areas)[-3:]))