2015: d12: ex2: add solution

2015/d12/ex2/ex2.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+
+import json
+import sys
+from collections.abc import Iterator
+
+JSONValue = int | str | list["JSONValue"] | dict[str, "JSONValue"]
+
+
+def solve(input: str) -> int:
+    def parse(input: str) -> JSONValue:
+        return json.loads(input)
+
+    def all_numbers(doc: JSONValue) -> Iterator[int]:
+        if isinstance(doc, int):
+            yield doc
+        elif isinstance(doc, list):
+            for it in doc:
+                yield from all_numbers(it)
+        elif isinstance(doc, dict):
+            if "red" in doc.values():
+                return
+            for it in doc.values():
+                yield from all_numbers(it)
+
+    doc = parse(input)
+    return sum(all_numbers(doc))
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()