2023.14

challenges/2023/14-parabolicReflectorDish/README.md

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+# [Day 14: Parabolic Reflector Dish](https://adventofcode.com/2023/day/14)

challenges/2023/14-parabolicReflectorDish/main.py

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+import sys
+from enum import Enum, auto
+
+
+def parse(instr: str) -> tuple[str]:
+    return tuple(instr.splitlines())
+
+
+class TiltDirection(Enum):
+    North = auto()
+    East = auto()
+    South = auto()
+    West = auto()
+
+
+def flip_platform(p: tuple[str]) -> tuple[str]:
+    return tuple(map(lambda x: "".join(x), zip(*p)))
+
+
+def tilt_platform(platform: tuple[str], direction: TiltDirection) -> tuple[str]:
+    if direction == TiltDirection.North or direction == TiltDirection.South:
+        platform = flip_platform(platform)
+
+    if direction == TiltDirection.North or direction == TiltDirection.West:
+        transformation = lambda x: x.replace(".O", "O.")
+    else:
+        transformation = lambda x: x.replace("O.", ".O")
+
+    res = []
+
+    for line in platform:
+        prev = ""
+        l = line
+        while prev != l:
+            prev = l
+            l = transformation(l)
+
+        res.append(l)
+
+    if direction == TiltDirection.North or direction == TiltDirection.South:
+        res = flip_platform(res)
+
+    return tuple(res)
+
+
+def calc_north_load(platform: tuple[str]) -> int:
+    acc = 0
+    for y, line in enumerate(platform):
+        for x, char in enumerate(line):
+            if char != "O":
+                continue
+            acc += len(platform) - y
+    return acc
+
+
+def one(instr: str):
+    platform = parse(instr)
+    platform = tilt_platform(platform, TiltDirection.North)
+    return calc_north_load(platform)
+
+
+def two(instr: str):
+    platform = parse(instr)
+
+    ITERS = 1_000_000_000
+
+    i = 0
+    known = {}
+    jumped = False
+    while i < ITERS:
+        for direction in [
+            TiltDirection.North,
+            TiltDirection.West,
+            TiltDirection.South,
+            TiltDirection.East,
+        ]:
+            platform = tilt_platform(platform, direction)
+
+        if not jumped:
+            if platform in known:
+                last_occurrence = known[platform]
+                period = i - last_occurrence
+                i += ((ITERS - i) // period) * period
+                jumped = True
+            else:
+                known[platform] = i
+        i += 1
+
+    return calc_north_load(platform)
+
+
+def _debug(*args, **kwargs):
+    kwargs["file"] = sys.stderr
+    print(*args, **kwargs)
+
+
+if __name__ == "__main__":
+    if len(sys.argv) < 2 or sys.argv[1] not in ["1", "2"]:
+        print("Missing day argument", file=sys.stderr)
+        sys.exit(1)
+    inp = sys.stdin.read().strip()
+    if sys.argv[1] == "1":
+        print(one(inp))
+    else:
+        print(two(inp))

challenges/2023/14-parabolicReflectorDish/tests.json

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+{
+    "1": [
+        {
+            "is": "136",
+            "input": "O....#....\nO.OO#....#\n.....##...\nOO.#O....O\n.O.....O#.\nO.#..O.#.#\n..O..#O..O\n.......O..\n#....###..\n#OO..#....\n\n"
+        }
+    ],
+    "2": [
+        {
+            "is": "64",
+            "input": "O....#....\nO.OO#....#\n.....##...\nOO.#O....O\n.O.....O#.\nO.#..O.#.#\n..O..#O..O\n.......O..\n#....###..\n#OO..#....\n\n"
+        }
+    ]
+}