2022: d06: ex2: add solution

2022/d06/ex2/ex2.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+
+import collections
+import itertools
+import sys
+from collections.abc import Iterable
+from typing import TypeVar
+
+T = TypeVar("T")
+
+
+def sliding_window(iterable: Iterable[T], n: int) -> Iterable[tuple[T, ...]]:
+    it = iter(iterable)
+    window = collections.deque(itertools.islice(it, n), maxlen=n)
+    if len(window) == n:
+        yield tuple(window)
+    for x in it:
+        window.append(x)
+        yield tuple(window)
+
+
+def solve(input: str) -> int:
+    SIZE = 14
+    for i, tup in enumerate(sliding_window(input, SIZE), start=SIZE):
+        if len(set(tup)) == SIZE:
+            return i
+    assert False
+
+
+def main() -> None:
+    input = sys.stdin.read().replace("\n", "")
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()