From dcdecaec5635d97ff22aa99e8c6ee5c45318a1b9 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Mon, 19 May 2025 00:58:08 +0100
Subject: [PATCH] 2016: d04: ex1: add solution

---
 2016/d04/ex1/ex1.py | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100755 2016/d04/ex1/ex1.py

diff --git a/2016/d04/ex1/ex1.py b/2016/d04/ex1/ex1.py
new file mode 100755
index 0000000..5c50645
--- /dev/null
+++ b/2016/d04/ex1/ex1.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+
+import collections
+import sys
+from typing import NamedTuple
+
+
+class Room(NamedTuple):
+    name: str
+    sector_id: int
+    checksum: str
+
+    def is_real(self) -> bool:
+        letters = collections.Counter(self.name.replace("-", ""))
+        checksum = sorted(letters.most_common(), key=lambda t: (-t[1], t[0]))[:5]
+        return "".join(c for c, _ in checksum) == self.checksum
+
+    @classmethod
+    def from_str(cls, input: str) -> "Room":
+        input, checksum = map(lambda s: s.removesuffix("]"), input.split("["))
+        *name, sector_id = input.split("-")
+        return cls("-".join(name), int(sector_id), checksum)
+
+
+def solve(input: str) -> int:
+    def parse(input: str) -> list[Room]:
+        return [Room.from_str(line) for line in input.splitlines()]
+
+    rooms = parse(input)
+    return sum(room.sector_id for room in rooms if room.is_real())
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()