2022: d03: ex2: add solution

2022/d03/ex2/ex2.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+
+import sys
+from collections.abc import Iterator
+
+Group = tuple[str, str, str]
+
+
+def solve(input: list[str]) -> int:
+    def score(lines: Group) -> int:
+        common_items = set(lines[0]) & set(lines[1]) & set(lines[2])
+        assert len(common_items) == 1  # Sanity check
+        common = common_items.pop()
+        return common.isupper() * 26 + ord(common.lower()) - ord("a") + 1
+
+    def iter_3() -> Iterator[Group]:
+        args = [iter(input)] * 3
+        yield from zip(*args, strict=True)  # type: ignore
+
+    return sum(map(score, iter_3()))
+
+
+def main() -> None:
+    input = sys.stdin.read().splitlines()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()