Day 13: Claw Contraption

README.md

@@ -17,4 +17,4 @@ Development occurs in language-specific directories:
 |[Day10.hs](hs/src/Day10.hs)|[Day10.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day10.kt)|[day10.py](py/aoc2024/day10.py)|[day10.rs](rs/src/day10.rs)|
 |[Day11.hs](hs/src/Day11.hs)|[Day11.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day11.kt)|[day11.py](py/aoc2024/day11.py)|[day11.rs](rs/src/day11.rs)|
 |[Day12.hs](hs/src/Day12.hs)|[Day12.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day12.kt)|[day12.py](py/aoc2024/day12.py)||
-|[Day12.hs](hs/src/Day12.hs)|[Day12.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day12.kt)|||
+|[Day13.hs](hs/src/Day13.hs)|[Day13.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day13.kt)|[day13.py](py/aoc2024/day13.py)||

py/aoc2024/day13.py

@@ -0,0 +1,52 @@
+"""
+Day 13: Claw Contraption
+"""
+
+import re
+from typing import Generator
+
+SAMPLE_INPUT = """
+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+26, Y+66
+Button B: X+67, Y+21
+Prize: X=12748, Y=12176
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+69, Y+23
+Button B: X+27, Y+71
+Prize: X=18641, Y=10279
+"""
+
+_pattern = re.compile(r"\d+")
+
+def _parse(data: str) -> Generator[tuple[int, int, int, int, int, int]]:
+    return zip(*((int(match.group(0)) for match in _pattern.finditer(data)),) * 6)
+
+def _solve(ax: int, ay: int, bx: int, by: int, x: int, y: int) -> int:
+    anumerator = x * by - y * bx
+    adenominator = ax * by - bx * ay
+    bnumerator = x * ay - y * ax
+    bdenominator = ay * bx - by * ax
+    if anumerator % adenominator or bnumerator % bdenominator:
+        return 0
+    a = anumerator // adenominator
+    b = bnumerator // bdenominator
+    return 3 * a + b
+
+def part1(data: str) -> int:
+    """
+    >>> part1(SAMPLE_INPUT)
+    480
+    """
+    return sum(_solve(ax, ay, bx, by, x, y) for ax, ay, bx, by, x, y in _parse(data))
+
+def part2(data: str) -> int:
+    return sum(_solve(ax, ay, bx, by, x + 10000000000000, y + 10000000000000) for ax, ay, bx, by, x, y in _parse(data))
+
+parts = (part1, part2)

py/pyproject.toml

@@ -36,6 +36,7 @@ day9 = "aoc2024.day9:parts"
 day10 = "aoc2024.day10:parts"
 day11 = "aoc2024.day11:parts"
 day12 = "aoc2024.day12:parts"
+day13 = "aoc2024.day13:parts"
 
 [build-system]
 requires = ["poetry-core"]