25-04 python

1 files changed, 36 insertions, 0 deletions

diff --git a/2025/04/python.py b/2025/04/python.py
new file mode 100755
index 0000000..844c38e
--- /dev/null
+++ b/2025/04/python.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+
+from fileinput import input
+
+g = {
+    complex(x, y): ch
+    for y, line in enumerate(input())
+    for x, ch in enumerate(line.strip())
+}
+
+
+def accessible():
+    return {
+        p
+        for p, x in g.items()
+        if x == "@"
+        and sum(
+            1
+            for dx in (-1, 0, 1)
+            for dy in (-1j, 0j, 1j)
+            if dx + dy != 0 and g.get(p + dx + dy, ".") == "@"
+        )
+        < 4
+    }
+
+
+silver = len(accessible())
+gold = 0
+
+while rem := accessible():
+    gold += len(rem)
+    for gone in rem:
+        g.pop(gone)
+
+print("silver:", silver)
+print("gold:", gold)