day 11

day11/input.txt

@@ -0,0 +1 @@
+0 89741 316108 7641 756 9 7832357 91

day11/part1.py

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+from __future__ import annotations
+
+import argparse
+import os.path
+
+import pytest
+
+import support
+
+INPUT_TXT = os.path.join(os.path.dirname(__file__), 'input.txt')
+
+
+def compute(s: str) -> int:
+    numbers = support.parse_numbers_split(s)
+
+    def _transmute(n: int) -> tuple[int, ...]:
+        if n == 0:
+            return (1,)
+        elif len(str(n)) % 2 == 0:
+            nstr = str(n)
+            midp = len(nstr) // 2
+            return int(nstr[:midp]), int(nstr[midp:])
+        else:
+            return (2024 * n,)
+
+    for _ in range(25):
+        numbers = [m for n in numbers for m in _transmute(n)]
+
+    return len(numbers)
+
+
+INPUT_S = '''\
+125 17
+'''
+EXPECTED = 55312
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected'),
+    (
+        (INPUT_S, EXPECTED),
+    ),
+)
+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())

day11/part2.py

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+from __future__ import annotations
+
+import argparse
+import functools
+import os.path
+
+import pytest
+
+import support
+
+INPUT_TXT = os.path.join(os.path.dirname(__file__), 'input.txt')
+
+
+@functools.cache
+def _compute(n: int, m: int) -> int:
+    if m == 0:
+        return 1
+    elif n == 0:
+        return _compute(1, m - 1)
+    elif len(str(n)) % 2 == 0:
+        nstr = str(n)
+        midp = len(nstr) // 2
+        return (
+            _compute(int(nstr[:midp]), m - 1) +
+            _compute(int(nstr[midp:]), m - 1)
+        )
+    else:
+        return _compute(2024 * n, m - 1)
+
+
+def compute(s: str, *, iterations: int = 75) -> int:
+    numbers = support.parse_numbers_split(s)
+
+    return sum(_compute(n, iterations) for n in numbers)
+
+
+INPUT_S = '''\
+125 17
+'''
+EXPECTED = 55312
+
+
+@pytest.mark.parametrize(
+    ('input_s', 'expected'),
+    (
+        (INPUT_S, EXPECTED),
+    ),
+)
+def test(input_s: str, expected: int) -> None:
+    assert compute(input_s, iterations=25) == 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())