From 4c511702fc5b2244c63560051e4994f9be309c7e Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Thu, 22 May 2025 00:43:54 +0100
Subject: [PATCH] 2015: d20: ex1: add solution

---
 2015/d20/ex1/ex1.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100755 2015/d20/ex1/ex1.py

diff --git a/2015/d20/ex1/ex1.py b/2015/d20/ex1/ex1.py
new file mode 100755
index 0000000..5892642
--- /dev/null
+++ b/2015/d20/ex1/ex1.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+
+import sys
+
+
+def solve(input: str) -> int:
+    needed = int(input.strip())
+    presents = [0] * (needed // 10)  # Surely this should be enough houses
+    for i in range(1, len(presents)):
+        for j in range(i, len(presents), i):
+            presents[j] += 10 * i
+    for i, total in enumerate(presents):
+        if total >= needed:
+            return i
+    assert False  # Sanity check
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()