2023.16

challenges/2023/16-theFloorWillBeLava/README.md

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+# [Day 16: The Floor Will Be Lava](https://adventofcode.com/2023/day/16)

challenges/2023/16-theFloorWillBeLava/main.py

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+import gridutil.grid as gu
+import gridutil.coord as cu
+from enum import Enum, auto
+import sys
+from collections import defaultdict
+
+
+class Direction(Enum):
+    Up = auto()
+    Down = auto()
+    Left = auto()
+    Right = auto()
+
+
+DIRECTION_DELTAS = {
+    Direction.Up: (0, -1),
+    Direction.Down: (0, 1),
+    Direction.Left: (-1, 0),
+    Direction.Right: (1, 0),
+}
+
+
+def parse(instr: str) -> gu.Grid:
+    return gu.parse(instr)
+
+
+def get_n_energised(
+    box: gu.Grid, start_pos: cu.Coordinate, start_directon: Direction
+) -> int:
+    energised = defaultdict(lambda: [])
+    beams = [(start_pos, start_directon)]
+
+    while beams:
+        (pos, direction) = beams.pop(0)
+
+        while True:
+            if pos not in box:
+                break
+
+            if pos in energised and direction in energised[pos]:
+                break
+            else:
+                energised[pos].append(direction)
+
+            at_pos = box[pos]
+
+            match at_pos:
+                case "/":
+                    match direction:
+                        case Direction.Up:
+                            direction = Direction.Right
+                        case Direction.Down:
+                            direction = Direction.Left
+                        case Direction.Left:
+                            direction = Direction.Down
+                        case Direction.Right:
+                            direction = Direction.Up
+
+                case "\\":
+                    match direction:
+                        case Direction.Up:
+                            direction = Direction.Left
+                        case Direction.Down:
+                            direction = Direction.Right
+                        case Direction.Left:
+                            direction = Direction.Up
+                        case Direction.Right:
+                            direction = Direction.Down
+
+                case "-":
+                    if not (
+                        direction == Direction.Left or direction == direction.Right
+                    ):
+                        beams.append(
+                            (
+                                (cu.add(pos, DIRECTION_DELTAS[Direction.Left])),
+                                Direction.Left,
+                            )
+                        )
+                        direction = Direction.Right
+
+                case "|":
+                    if not (direction == Direction.Up or direction == direction.Down):
+                        beams.append(
+                            (
+                                (cu.add(pos, DIRECTION_DELTAS[Direction.Up])),
+                                Direction.Up,
+                            )
+                        )
+                        direction = Direction.Down
+
+            pos = cu.add(pos, DIRECTION_DELTAS[direction])
+
+    return len(energised)
+
+
+def one(instr: str):
+    box = parse(instr)
+    return get_n_energised(box, (0, 0), Direction.Right)
+
+
+def two(instr: str):
+    box = parse(instr)
+
+    max_x = gu.get_max_x(box)
+    max_y = gu.get_max_y(box)
+
+    starts = [(0, y) for y in range(max_y + 1)]
+    starts += [(max_x, y) for y in range(max_y + 1)]
+    starts += [(x, 0) for x in range(1, max_x)]
+    starts += [(x, max_y) for x in range(1, max_x)]
+
+    max_energised = 0
+
+    for start in starts:
+        for direction in Direction:
+            x = get_n_energised(box, start, direction)
+            if x > max_energised:
+                max_energised = x
+
+    return max_energised
+
+
+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/2023/16-theFloorWillBeLava/test.txt

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+.|...\....
+|.-.\.....
+.....|-...
+........|.
+..........
+.........\
+..../.\\..
+.-.-/..|..
+.|....-|.\
+..//.|....

challenges/2023/16-theFloorWillBeLava/tests.json

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+{
+    "1": [
+        {
+            "is": "46",
+            "input": ".|...\\....\n|.-.\\.....\n.....|-...\n........|.\n..........\n.........\\\n..../.\\\\..\n.-.-/..|..\n.|....-|.\\\n..//.|....\n"
+        }
+    ],
+    "2": [
+        {
+            "is": "51",
+            "input": ".|...\\....\n|.-.\\.....\n.....|-...\n........|.\n..........\n.........\\\n..../.\\\\..\n.-.-/..|..\n.|....-|.\\\n..//.|....\n"
+        }
+    ]
+}

challenges/2023/README.md

@@ -29,3 +29,4 @@ A day denoted with a star means it has a visualisation.
 | 13 - Point of Incidence | ★ ★ | Python | This one made me feel slightly intelligent. |
 | 14* - Parabolic Reflector Dish | ★ ★ | Python | Why do I always overcomplicate cycle detection?! |
 | 15 - Lens Library | ★ ★ | Go | Still took some brainpower but this time the brainpower was needed to work out what the problem was, *not* to work out how to solve the problem. |
+| 16 - The Floor Will Be Lava | ★ ★ | Python | Pathfinding, sort of, but also brute forceable?? |

challenges/2023/benchmarks.jsonl

@@ -27,3 +27,5 @@
 {"day": 14, "part": 2, "runner": "py", "min": 0.48926782608032227, "max": 0.6927425861358643, "avg": 0.5653452634811401, "n": 50}
 {"day": 15, "part": 1, "runner": "go", "min": 0.0005846023559570312, "max": 0.0011608600616455078, "avg": 0.0007052874565124512, "n": 100}
 {"day": 15, "part": 2, "runner": "go", "min": 0.0012998580932617188, "max": 0.0028612613677978516, "avg": 0.0014359498023986817, "n": 100}
+{"day": 16, "part": 1, "runner": "py", "min": 0.030925512313842773, "max": 0.03607058525085449, "avg": 0.03239912986755371, "n": 10}
+{"day": 16, "part": 2, "runner": "py", "min": 2.7083919048309326, "max": 5.615460634231567, "avg": 4.0310279607772825, "n": 10}