Add Day 8: Part 1

Author: juergenhoetzel

README.md

@@ -2,12 +2,13 @@
 
 ## Solutions
 
-| Advent of Code Page                                              | Part 1 | Part 2 | Day                    |
-|------------------------------------------------------------------|--------|--------|------------------------|
-| [Day 1: Historian Hysteria](https://adventofcode.com/2024/day/1) | ✅     | ✅     | [day1.py](aoc/day1.py) |
-| [Day 2: Red-Nosed Reports](https://adventofcode.com/2024/day/2)  | ✅     | ✅     | [day2.py](aoc/day2.py) |
-| [Day 3: Mull It Over](https://adventofcode.com/2024/day/3)       | ✅     | ✅     | [day3.py](aoc/day3.py) |
-| [Day 4: Ceres Search](https://adventofcode.com/2024/day/4)       | ✅     | ✅     | [day4.py](aoc/day4.py) |
-| [Day 5: Print Queue](https://adventofcode.com/2024/day/5)        | ✅     | ✅     | [day5.py](aoc/day5.py) |
-| [Day 6: Guard Gallivant](https://adventofcode.com/2024/day/6)    | ✅     | ✅     | [day6.py](aoc/day6.py) |
-| [Day 7: Bridge Repair](https://adventofcode.com/2024/day/7)      | ✅     | ✅     | [day7.py](aoc/day7.py) |
+| Advent of Code Page                                                 | Part 1 | Part 2 | Day                    |
+|---------------------------------------------------------------------|--------|--------|------------------------|
+| [Day 1: Historian Hysteria](https://adventofcode.com/2024/day/1)    | ✅     | ✅     | [day1.py](aoc/day1.py) |
+| [Day 2: Red-Nosed Reports](https://adventofcode.com/2024/day/2)     | ✅     | ✅     | [day2.py](aoc/day2.py) |
+| [Day 3: Mull It Over](https://adventofcode.com/2024/day/3)          | ✅     | ✅     | [day3.py](aoc/day3.py) |
+| [Day 4: Ceres Search](https://adventofcode.com/2024/day/4)          | ✅     | ✅     | [day4.py](aoc/day4.py) |
+| [Day 5: Print Queue](https://adventofcode.com/2024/day/5)           | ✅     | ✅     | [day5.py](aoc/day5.py) |
+| [Day 6: Guard Gallivant](https://adventofcode.com/2024/day/6)       | ✅     | ✅     | [day6.py](aoc/day6.py) |
+| [Day 7: Bridge Repair](https://adventofcode.com/2024/day/7)         | ✅     | ✅     | [day7.py](aoc/day7.py) |
+| [Day 8: Resonant Collinearity](https://adventofcode.com/2024/day/8) | ✅     | ❌     | [day8.py](aoc/day8.py) |

aoc/day8.py

@@ -0,0 +1,47 @@
+import sys
+from dataclasses import dataclass
+from itertools import combinations
+from pathlib import Path
+
+
+@dataclass
+class AntennaMap:
+    rows: int
+    cols: int
+    positions: dict[str, set[tuple[int, int]]]
+
+
+def parse_input(lines: list[str]) -> AntennaMap:
+    positions = [(c, (y, x)) for y, line in enumerate(lines) for x, c in enumerate(line) if c != "."]
+    antennamap = {}
+    for c, pos in positions:
+        antennamap[c] = antennamap.get(c, set()) | {pos}
+    return AntennaMap(len(lines), len(lines[0]), antennamap)
+
+
+def positions(am: AntennaMap) -> set[tuple[int, int]]:
+    anodes_pos = set()
+
+    def is_in_field(pos):
+        y, x = pos
+        return 0 <= y < am.rows and 0 <= x < am.cols
+
+    for _, positions in am.positions.items():
+        for (y1, x1), (y2, x2) in combinations(positions, 2):
+            anodes_pos |= {
+                pos for pos in [(y1 + (y1 - y2), x1 + (x1 - x2)), (y2 + (y2 - y1), x2 + (x2 - x1))] if is_in_field(pos)
+            }
+    return anodes_pos
+
+
+def part1(am: AntennaMap) -> int:
+    return len(positions(am))
+
+
+def main():
+    lines = parse_input(Path(sys.argv[1]).read_text().splitlines())
+    print(f"Part 1: {part1(lines)}")
+
+
+if __name__ == "__main__":
+    main()

test/test_day8.py

@@ -0,0 +1,19 @@
+from aoc.day8 import parse_input, part1
+
+TEST_INPUT = """............
+........0...
+.....0......
+.......0....
+....0.......
+......A.....
+............
+............
+........A...
+.........A..
+............
+............
+""".splitlines()
+
+
+def test_part1():
+    assert part1(parse_input(TEST_INPUT)) == 14