feat: add 2023 day 09

Author: marcelblijleven

src/adventofcode/year_2023/day_09_2023.py

@@ -0,0 +1,78 @@
+import re
+from functools import partial
+from itertools import pairwise
+from operator import itemgetter
+from typing import Iterable
+
+from adventofcode.util.exceptions import SolutionNotFoundError
+from adventofcode.registry.decorators import register_solution
+from adventofcode.util.input_helpers import get_input_for_day
+
+
+pattern = re.compile("-?\\d+")
+
+
+def parse_sequence(sequence: str) -> Iterable[int]:
+    return map(int, pattern.findall(sequence))
+
+
+def parse_sequence_backwards(sequence: str) -> Iterable[int]:
+    return reversed(list(map(int, pattern.findall(sequence))))
+
+
+def parse_input(data: list[str]) -> Iterable[Iterable[int]]:
+    return map(parse_sequence, data)
+
+
+def parse_input_reversed(data: list[str]) -> Iterable[Iterable[int]]:
+    return map(parse_sequence_backwards, data)
+
+
+def find_next_in_sequence(sequence: Iterable[int], lines: list[list[int]] | None) -> int:
+    numbers = list(sequence)
+    lines = [numbers] if lines is None or len(lines) == 0 else lines
+    differences = [y-x for (x, y) in pairwise(numbers)]
+    lines.append(differences)
+
+    if any(differences):
+        return find_next_in_sequence(differences, lines)
+
+    return sum(map(itemgetter(-1), lines))
+
+
+def solve_part_one(data: list[str]) -> int:
+    parsed_input = parse_input(data)
+    find_next = partial(find_next_in_sequence, lines=None)
+    return sum(map(find_next, parsed_input))
+
+
+def solve_part_two(data: list[str]) -> int:
+    parsed_input = parse_input_reversed(data)
+    find_next = partial(find_next_in_sequence, lines=None)
+    return sum(map(find_next, parsed_input))
+
+
+@register_solution(2023, 9, 1)
+def part_one(input_data: list[str]):
+    answer = solve_part_one(input_data)
+
+    if not answer:
+        raise SolutionNotFoundError(2023, 9, 1)
+
+    return answer
+
+
+@register_solution(2023, 9, 2)
+def part_two(input_data: list[str]):
+    answer = solve_part_two(input_data)
+
+    if not answer:
+        raise SolutionNotFoundError(2023, 9, 2)
+
+    return answer
+
+
+if __name__ == '__main__':
+    data = get_input_for_day(2023, 9)
+    part_one(data)
+    part_two(data)

tests/adventofcode/year_2023/test_day_09_2023.py

@@ -0,0 +1,45 @@
+import pytest
+
+from adventofcode.year_2023.day_09_2023 import part_two, part_one, parse_input, parse_sequence, find_next_in_sequence
+
+test_input = [
+    "0 3 6 9 12 15",
+    "1 3 6 10 15 21",
+    "10 13 16 21 30 45",
+]
+
+
+@pytest.mark.parametrize(["sequence", "expected"], [
+    ("0 3 6 9 12 15", [0, 3, 6, 9, 12, 15]),
+    ("1 3 6 10 15 21", [1, 3, 6, 10, 15, 21]),
+    ("10 13 16 21 30 45", [10, 13, 16, 21, 30, 45]),
+    ("-1 -20 -300 400", [-1, -20, -300, 400]),
+    ("5 1 -3 -7 -11 -15 -19 -23 -27 -31 -35 -39 -43 -47 -51 -55 -59 -63 -67 -71 -75", [5, 1, -3, -7, -11, -15, -19, -23, -27, -31, -35, -39, -43, -47, -51, -55, -59, -63, -67, -71, -75]),
+])
+def test_parse_sequence(sequence, expected):
+    assert list(parse_sequence(sequence)) == expected
+
+
+def test_parse_input():
+    assert len(list(parse_input(test_input))) == 3
+
+
+@pytest.mark.parametrize(["sequence", "expected"], [
+    ([13, 23, 46, 97, 206, 436, 919, 1924, 3971, 8016, 15765, 30243, 56875, 105604, 195153, 361805, 677725, 1289089,
+      2494076, 4898137, 9713336], 19316320),
+    ([-7, 6, 44, 130, 309, 672, 1404, 2864, 5712, 11113, 21082, 39112, 71386, 129156, 233312, 422773, 769075,
+      1400300, 2538072, 4551386, 8029995], 13877188
+     ),
+    ([5, 1, -3, -7, -11, -15, -19, -23, -27, -31, -35, -39, -43, -47, -51, -55, -59, -63, -67, -71, -75,
+], -79)
+])
+def test_find_next_in_sequence(sequence, expected):
+    assert find_next_in_sequence(sequence, []) == expected
+
+
+def test_part_one():
+    assert part_one(test_input) == 114
+
+
+def test_part_two():
+    assert part_two(test_input) == 'x'