Day 23: Python

Quite slow: Time (mean ± σ): 927.7 ms ± 3.8 ms

23/example.txt

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+kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn

23/python/solution.py

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+#!/usr/bin/env python3
+"""AoC day 23, 2024: LAN Party"""
+
+import pathlib
+import sys
+from collections import defaultdict
+
+
+def parse_data(puzzle_input: str) -> dict[str, set]:
+    """Parse input data"""
+    graph = defaultdict(set)
+    edges = [line.strip().split("-") for line in puzzle_input.splitlines()]
+
+    for x, y in edges:
+        graph[x].add(y)
+        graph[y].add(x)
+
+    return graph
+
+
+def part1(graph: dict[str, set]) -> int:
+    """Solve part 1"""
+    sets = set()
+
+    for x in graph:
+        for y in graph[x]:
+            for z in graph[y]:
+                if z != x and x in graph[z]:
+                    sets.add((tuple(sorted([x, y, z]))))
+
+    return len([s for s in sets if any(n.startswith("t") for n in s)])
+
+
+def part2(graph: dict[str, set]) -> str:
+    """Solve part 2"""
+    sets = set()
+
+    def search(node: str, required: set):
+        key = tuple(sorted(required))
+        if key in sets:
+            return
+
+        sets.add(key)
+
+        for neighbor in graph[node]:
+            if neighbor in required:
+                continue
+            if not required <= graph[neighbor]:
+                continue
+
+            search(neighbor, {*required, neighbor})
+
+    for node in graph:
+        search(node, {node})
+
+    return ",".join(sorted(max(sets, key=len)))
+
+
+def solve(puzzle_input: str) -> tuple[int, str]:
+    """Solve the puzzle for the given input"""
+    data = parse_data(puzzle_input)
+    return part1(data), part2(data)
+
+
+if __name__ == "__main__":
+    for path in sys.argv[1:]:
+        print(f"\n{path}:")
+        solutions = solve(pathlib.Path(path).read_text().strip())
+        print("\n".join(str(solution) for solution in solutions))

23/python/test_solution.py

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+#!/usr/bin/env python3
+"""Tests for AoC day 23, 2024: LAN Party"""
+
+from pathlib import Path
+
+import pytest
+
+from solution import parse_data, part1, part2
+
+
+@pytest.fixture
+def example_data() -> str:
+    current_dir = Path(__file__).parent
+    filename = current_dir.parent / "example.txt"
+    try:
+        return filename.read_text().strip()
+    except FileNotFoundError:
+        raise FileNotFoundError(f"Example input file not found at {filename}")
+
+
+def test_parse(example_data: str) -> None:
+    data = parse_data(example_data)
+    assert len(data) > 0
+
+
+def test_part1(example_data: str) -> None:
+    data = parse_data(example_data)
+    assert part1(data) == 7
+
+
+def test_part2(example_data: str) -> None:
+    data = parse_data(example_data)
+    assert part2(data) == "co,de,ka,ta"