Add 2024 day 8 solutions

1 files changed, 40 insertions, 0 deletions

diff --git a/2024/08/puzzles.py b/2024/08/puzzles.py
new file mode 100644
index 0000000..87c4c46
--- /dev/null
+++ b/2024/08/puzzles.py
@@ -0,0 +1,40 @@
+#!/usr/bin/python3
+
+import collections
+import itertools
+
+
+type Antennas = defaultdict[str, list[complex]]
+
+
+def main() -> None:
+	with open("input", "r") as f:
+		data = [x.rstrip() for x in f.readlines()]
+	w, h = len(data[0]), len(data)
+
+	antennas: Antennas = collections.defaultdict(list)
+	antinodes: set[complex] = set()
+
+	for y, row in enumerate(data):
+		for x, ch in enumerate(row):
+			if ch != '.':
+				antennas[ch].append(complex(x, y))
+
+	for coords in antennas.values():
+		for a, b in itertools.combinations(coords, 2):
+			v⃗ = a - b
+			u⃗ = b - a
+			# START PART 1
+			antinodes.add(a + u⃗*2)
+			antinodes.add(b + v⃗*2)
+			# END PART 1 START PART 2
+			for i in range(1, max(w, h)):
+				antinodes.add(a + u⃗*i)
+				antinodes.add(b + v⃗*i)
+			# END PART 2
+
+	print(sum(0 <= x.real < w and 0 <= x.imag < h for x in antinodes))
+
+
+if __name__ == "__main__":
+	main()
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