2019: d16: ex1: add solution

2019/d16/ex1/ex1.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+
+import sys
+from functools import reduce
+from itertools import chain, cycle
+from typing import Iterable, List
+
+
+def sequencer(pattern: List[int], n: int) -> Iterable[int]:
+    gen = cycle(list(chain(*([a] * n for a in pattern))))
+    next(gen)  # Skip the first one
+    yield from gen
+
+
+def main() -> None:
+    signal = [int(d) for d in sys.stdin.read().strip()]
+    base_pattern = [0, 1, 0, -1]
+
+    for __ in range(100):
+        signal = [
+            abs(sum(a * b for a, b in zip(signal, sequencer(base_pattern, i + 1)))) % 10
+            for i in range(len(signal))
+        ]
+
+    print(reduce(lambda a, b: a * 10 + b, signal[0:8]))
+
+
+if __name__ == "__main__":
+    main()