Add day 3 solutions

1 files changed, 30 insertions, 0 deletions

diff --git a/2021/03/puzzle-2.py b/2021/03/puzzle-2.py
new file mode 100755
index 0000000..c5ae894
--- /dev/null
+++ b/2021/03/puzzle-2.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+from copy import deepcopy
+from typing import Callable
+
+
+def solve(lines: list[str], comp: Callable[[int, int], bool]) -> int:
+	while True:
+		for i in range(len(lines[0])):
+			if len(lines) == 1:
+				return int(lines[0], 2)
+
+			ones = len([line for line in lines if line[i] == "1"])
+			zeros = len([line for line in lines if line[i] == "0"])
+
+			if comp(zeros, ones):
+				lines = [line for line in lines if line[i] == "0"]
+			else:
+				lines = [line for line in lines if line[i] == "1"]
+
+
+def main() -> None:
+	with open("input", "r", encoding="utf-8") as f:
+		data = [l.strip() for l in f.readlines()]
+
+	print(solve(deepcopy(data), lambda x, y: x > y) * solve(data, lambda x, y: x <= y))
+
+
+if __name__ == "__main__":
+	main()