readme

day06/part2.py

@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+import argparse
+import os.path
+from collections import deque
+
+import pytest
+
+import support
+
+INPUT_TXT = os.path.join(os.path.dirname(__file__), 'input.txt')
+
+
+def compute(s: str):
+    four_window = deque(maxlen=14)
+    for idx, char in enumerate(s):
+        if char in four_window:
+            four_window.clear()
+        elif len(four_window) == 13:
+            return idx
+        four_window.append(char)
+    raise Exception('no answer')
+
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected'),
+    (("mjqjpqmgbljsphdztnvjfqwrcgsmlb", 7))
+)
+
+def test(input_s: str, expected: int) -> None:
+    assert compute(input_s) == expected
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('data_file', nargs='?', default=INPUT_TXT)
+    args = parser.parse_args()
+
+    with open(args.data_file) as f, support.timing():
+        print(compute(f.read()))
+
+    return 0
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())