Add 2025 day 9 solutions

2 files changed, 78 insertions, 0 deletions

diff --git a/2025/09/puzzle-1.py b/2025/09/puzzle-1.py
new file mode 100755
index 0000000..6d42141
--- /dev/null
+++ b/2025/09/puzzle-1.py
@@ -0,0 +1,29 @@
+#!/usr/bin/python3
+
+import itertools
+
+
+type Point = tuple[int, int]
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		xs = [tuple(map(int, l.split(','))) for l in f.readlines()]
+
+	it = itertools.combinations(xs, 2)
+	it = itertools.starmap(area, it)
+	print(max(it))
+
+
+def area(p: Point, q: Point) -> int:
+	a, b = minmax(p[0], q[0])
+	c, d = minmax(p[1], q[1])
+	return (b - a + 1) * (d - c + 1)
+
+
+def minmax(x: int, y: int) -> tuple[int, int]:
+	return (x, y) if x < y else (y, x)
+
+
+if __name__ == '__main__':
+	main()
diff --git a/2025/09/puzzle-2.py b/2025/09/puzzle-2.py
new file mode 100755
index 0000000..f77c4c1
--- /dev/null
+++ b/2025/09/puzzle-2.py
@@ -0,0 +1,49 @@
+#!/usr/bin/python3
+
+import itertools
+
+
+type Point = tuple[int, int]
+type Box = tuple[int, int, int, int]
+
+
+def main() -> None:
+	with open('input', 'r') as f:
+		xs = [tuple(map(int, l.split(','))) for l in f.readlines()]
+
+	it = itertools.pairwise(xs)
+	it = itertools.starmap(tobox, it)
+	ys = list(it)
+
+	n = 0
+	it = itertools.combinations(xs, 2)
+	it = itertools.starmap(tobox, it)
+	for x in it:
+		if (_area := area(x)) <= n:
+			continue
+		a, b, c, d = x
+		for p, q, r, s in ys:
+			if a < r and b < s and c > p and d > q:
+				break
+		else:
+			n = _area
+
+	print(n)
+
+
+def tobox(p: Point, q: Point) -> Box:
+	a, b = minmax(p[0], q[0])
+	c, d = minmax(p[1], q[1])
+	return a, c, b, d
+
+
+def area(b: Box) -> int:
+	return (b[2] - b[0] + 1) * (b[3] - b[1] + 1)
+
+
+def minmax(x: int, y: int) -> tuple[int, int]:
+	return (x, y) if x < y else (y, x)
+
+
+if __name__ == '__main__':
+	main()