day06 finished

advent/days/day06/solution.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+from itertools import product
+from typing import Iterator
+
+day_num = 6
+
+
+def part1(lines: Iterator[str]) -> int:
+    return marker(next(lines), 4)
+
+
+def part2(lines: Iterator[str]) -> int:
+    return marker(next(lines), 14)
+
+
+def marker(line: str, length: int) -> int:
+    """
+    Returns the position just after a marker. A marker has [length] non repeated characters.
+    Raises Exception if no marker was found
+    """
+    for pos in range(length, len(line)):
+        identical = 0
+        for a, b in product(line[pos - length:pos], repeat=2):
+            if a == b:
+                identical += 1
+        if identical == length:
+            return pos
+
+    raise Exception("No marker found")