From bc79fa83d3cb63d8445312b47dbed9295809b28a Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Thu, 4 Dec 2025 06:34:16 +0100
Subject: Day 4 2025

---
 2025/04/b.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 2025/04/b.py

(limited to '2025/04/b.py')

diff --git a/2025/04/b.py b/2025/04/b.py
new file mode 100644
index 0000000..93b1fff
--- /dev/null
+++ b/2025/04/b.py
@@ -0,0 +1,26 @@
+import fileinput
+
+def neigh(a, i, j):
+	return [
+		a[i-1][j-1], a[i-1][j], a[i-1][j+1],
+		a[i][j-1],              a[i][j+1],
+		a[i+1][j-1], a[i+1][j], a[i+1][j+1],
+	].count('@')
+
+s = 0
+with fileinput.input() as lines:
+	a = [['.'] * 200]
+	for line in lines:
+		a.append(['.'] + list(line.replace('\n', '.')))
+	a.append(['.'] * 200)
+
+rem = True
+while rem:
+	rem = False
+	for i in range(1,len(a)-1):
+		for j in range(1,len(a[1])-1):
+			if a[i][j] == '@' and neigh(a, i, j) < 4:
+				s += 1
+				rem = True
+				a[i][j] = '.'
+print(s)
-- 
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