From 22dec5e521e5b7391850684d0d891391d12e6cb5 Mon Sep 17 00:00:00 2001
From: Kees van Kempen <git@keesvankempen.nl>
Date: Fri, 5 Dec 2025 09:42:33 +0100
Subject: [PATCH] 2025(04): solve part 2, change to function to what they
 should have been in 1

---
 2025/04/part1.py |  8 ++++++--
 2025/04/part2.py | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 2025/04/part2.py

diff --git a/2025/04/part1.py b/2025/04/part1.py
index d2a6831..3adb6dc 100644
--- a/2025/04/part1.py
+++ b/2025/04/part1.py
@@ -36,14 +36,18 @@ def count_neighbours(tp_map):
 		dX, dY = X.copy() + x, Y.copy() + y
 		legal_idx = (dX >= 0)*(dX < L_x)*(dY >= 0)*(dY < L_y)*((dX != x)|(dY != y))
 		neighbour_counts[x, y] = (tp_map[dX[legal_idx], dY[legal_idx]]).sum()
+	return neighbour_counts
+
+def count_extractable(tp_map):
+	neighbour_counts = count_neighbours(tp_map)
 	max_rolls = 4
 	return (neighbour_counts[tp_map] < max_rolls).sum()
 
 if __name__ == "__main__":
 	test_map = read_map("testinput")
 	# print(test_map)
-	assert count_neighbours(test_map) == 13
+	assert count_extractable(test_map) == 13
 	# TODO: Compare the output map.
 
 	real_map = read_map("input")
-	print(count_neighbours(real_map))
\ No newline at end of file
+	print(count_extractable(real_map))
\ No newline at end of file
diff --git a/2025/04/part2.py b/2025/04/part2.py
new file mode 100644
index 0000000..b276561
--- /dev/null
+++ b/2025/04/part2.py
@@ -0,0 +1,24 @@
+import numpy as np
+from part1 import read_map, print_map, count_neighbours, count_extractable
+
+def remove_iteratively(tp_map):
+	max_rolls = 4
+	rolls_removed_counts = []
+	rolls_removed_count = 1_000_000
+	while rolls_removed_count > 0:
+		neighbour_counts = count_neighbours(tp_map)
+		rolls_to_remove = (neighbour_counts < max_rolls)*tp_map
+		rolls_removed_count = rolls_to_remove.sum()
+		rolls_removed_counts.append(rolls_removed_count)
+		tp_map[rolls_to_remove] = False
+	return sum(rolls_removed_counts)
+
+if __name__ == "__main__":
+	test_map = read_map("testinput")
+	# print(test_map)
+	assert count_extractable(test_map) == 13
+	assert remove_iteratively(test_map.copy()) == 43
+	# TODO: Compare the output maps.
+
+	real_map = read_map("input")
+	print(remove_iteratively(real_map.copy()))
\ No newline at end of file