From ed395fe7a7fd68f6db4ea94de8fdcdcb0fac5179 Mon Sep 17 00:00:00 2001
From: bthink <bthink@fake.com>
Date: Sun, 7 Dec 2025 15:59:37 +0100
Subject: first week of AOC 2025

---
 2025/aoc2025-d04.py | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 2025/aoc2025-d04.py

(limited to '2025/aoc2025-d04.py')

diff --git a/2025/aoc2025-d04.py b/2025/aoc2025-d04.py
new file mode 100644
index 0000000..46e7578
--- /dev/null
+++ b/2025/aoc2025-d04.py
@@ -0,0 +1,31 @@
+#advent of code 2025
+#day 04
+part1=0;
+part2=0;
+wall=set();
+PuzzleInput=open("04.in","r");
+adjacent=[(-1,-1),(0,-1),(1,-1),(-1,0),(1,0),(-1,1),(0,1),(1,1)];
+def IsAccessible(grid,p):
+	neighbors=0;
+	px,py=p;
+	for dx,dy in adjacent:
+		neighbors+=(px+dx,py+dy) in grid;
+	return neighbors<4;
+#parsing
+for y,line in enumerate(PuzzleInput):
+	for x,c in enumerate(line[:-1]):
+		if c=="@": wall.add((x,y));
+PuzzleInput.close();
+#solution
+while True:
+	removed=set();
+	for pos in wall:
+		if IsAccessible(wall,pos):
+			removed.add(pos);
+	if len(removed)==0: break;
+	wall.difference_update(removed);
+	if part1==0: part1+=len(removed);
+	part2+=len(removed);
+#answers
+print("part 1",part1);
+print("part 2",part2);
-- 
cgit v1.2.3