2023.18

challenges/2023/18-lavaductLagoon/README.md

@@ -0,0 +1 @@
+# [Day 18: Lavaduct Lagoon](https://adventofcode.com/2023/day/18)

challenges/2023/18-lavaductLagoon/main.py

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+import sys
+import re
+from collections import namedtuple
+import gridutil.coord as cu
+import gridutil.grid as gu
+
+
+Instruction = namedtuple("Instruction", ["direction", "dist", "colour"])
+PARSE_RE = re.compile(r"([RDUL]) (\d+) \(#([a-f\d]{6})\)")
+DIRECTION_TRANSFORMATION = {
+    "R": cu.Direction.Right,
+    "L": cu.Direction.Left,
+    "U": cu.Direction.Up,
+    "D": cu.Direction.Down,
+    "0": cu.Direction.Right,
+    "1": cu.Direction.Down,
+    "2": cu.Direction.Left,
+    "3": cu.Direction.Up,
+}
+
+
+def parse(instr: str) -> list[Instruction]:
+    res = []
+    for line in instr.splitlines():
+        m = PARSE_RE.match(line)
+        assert m is not None
+
+        raw_dir, dist, colour = m.groups()
+        parsed_dir = DIRECTION_TRANSFORMATION[raw_dir]
+        assert parsed_dir is not None
+
+        res.append(Instruction(parsed_dir, int(dist), colour))
+    return res
+
+
+def run(instructions: list[Instruction]) -> int:
+    perimeter = 0
+    vertices = [cu.Coordinate(0, 0)]
+    for instruction in instructions:
+        perimeter += instruction.dist
+        vertices.append(
+            cu.add(
+                vertices[-1], cu.mult(instruction.direction.delta(), instruction.dist)
+            )
+        )
+
+    vertices = vertices[:-1]
+
+    area = cu.area(vertices)
+
+    # This is Pick's theorem.
+    # Normally, we'd want to just get the internal area, which the Shoelace formula would do.
+    # But since we want the area including walls that we assume are a single
+    # unit thick, we apply Pick's theorem as this counts all coordinates that
+    # the walls pass through, which in this case is effectively the same thing.
+    return int(area + perimeter / 2) + 1
+
+
+def one(instr: str):
+    instructions = parse(instr)
+    return run(instructions)
+
+
+def two(instr: str):
+    instructions = parse(instr)
+    for i, instruction in enumerate(instructions):
+        instructions[i] = Instruction(
+            DIRECTION_TRANSFORMATION[instruction.colour[-1]],
+            int(instruction.colour[:5], base=16),
+            "",
+        )
+    return run(instructions)
+
+
+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/2023/18-lavaductLagoon/tests.json

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+{
+    "1": [
+        {
+            "is": "62",
+            "input": "R 6 (#70c710)\nD 5 (#0dc571)\nL 2 (#5713f0)\nD 2 (#d2c081)\nR 2 (#59c680)\nD 2 (#411b91)\nL 5 (#8ceee2)\nU 2 (#caa173)\nL 1 (#1b58a2)\nU 2 (#caa171)\nR 2 (#7807d2)\nU 3 (#a77fa3)\nL 2 (#015232)\nU 2 (#7a21e3)\n\n"
+        },
+        {
+            "is": "20",
+            "input": "R 2 (#000000)\nD 1 (#000000)\nR 2 (#000000)\nU 1 (#000000)\nR 2 (#000000)\nD 2 (#000000)\nL 6 (#000000)\nU 2 (#000000)\n"
+        }
+    ],
+    "2": [
+        {
+            "is": "952408144115",
+            "input": "R 6 (#70c710)\nD 5 (#0dc571)\nL 2 (#5713f0)\nD 2 (#d2c081)\nR 2 (#59c680)\nD 2 (#411b91)\nL 5 (#8ceee2)\nU 2 (#caa173)\nL 1 (#1b58a2)\nU 2 (#caa171)\nR 2 (#7807d2)\nU 3 (#a77fa3)\nL 2 (#015232)\nU 2 (#7a21e3)\n\n"
+        }
+    ]
+}

challenges/2023/README.md

@@ -30,4 +30,5 @@ A day denoted with a star means it has a visualisation.
 | 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?? |
-| 17 - Clumsy Crucible | ★ ★ | Python | This taught me quite a lot about how to meddle with Djikstra's |
+| 17 - Clumsy Crucible | ★ ★ | Python | This taught me quite a lot about how to meddle with Djikstra's |
+| 18 - Ladaduct Lagoon | ★ ★ | Python | Nothing quite like a problem that I thought I knew the solution to showing up my lack of mathematical knowledge. |

challenges/2023/benchmarks.jsonl

@@ -31,3 +31,5 @@
 {"day": 16, "part": 2, "runner": "py", "min": 2.7863943576812744, "max": 4.14529013633728, "avg": 3.1346225261688234, "n": 15}
 {"day": 17, "part": 1, "runner": "py", "min": 5.36311674118042, "max": 5.36311674118042, "avg": 5.36311674118042, "n": 1}
 {"day": 17, "part": 2, "runner": "py", "min": 26.201914072036743, "max": 26.201914072036743, "avg": 26.201914072036743, "n": 1}
+{"day": 18, "part": 1, "runner": "py", "min": 0.02330160140991211, "max": 0.03203868865966797, "avg": 0.024628419876098633, "n": 100}
+{"day": 18, "part": 2, "runner": "py", "min": 0.023529052734375, "max": 0.030207157135009766, "avg": 0.02483478546142578, "n": 100}