From 603fb558d957201754cc3e64004f83e2f9ff4745 Mon Sep 17 00:00:00 2001
From: Thomas Voss <mail@thomasvoss.com>
Date: Sun, 11 Dec 2022 22:48:48 +0100
Subject: Add 2022 day 9 solutions

---
 2022/09/puzzles.py | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 2022/09/puzzles.py

(limited to '2022/09/puzzles.py')

diff --git a/2022/09/puzzles.py b/2022/09/puzzles.py
new file mode 100644
index 0000000..565a39c
--- /dev/null
+++ b/2022/09/puzzles.py
@@ -0,0 +1,68 @@
+#!/usr/bin/python3
+
+# START PART 1
+SEGMENTS = 2
+# END PART 1 START PART 2
+SEGMENTS = 10
+# END PART 2
+
+position = tuple[int, int]
+
+
+class Segment:
+	def __init__(self):
+		self.x = 0
+		self.y = 0
+
+	def track(self, pos: position) -> None:
+		x, y = pos
+		dx = x - self.x
+		dy = y - self.y
+		nx = 1 if dx > 0 else -1
+		ny = 1 if dy > 0 else -1
+
+		match (abs(dx), abs(dy)):
+			case (2, 0):
+				self.x += nx
+			case (0, 2):
+				self.y += ny
+			case (2, 1) | (2, 2) | (1, 2):
+				self.x += nx
+				self.y += ny
+
+	@property
+	def pos(self) -> position:
+		return self.x, self.y
+
+
+def main() -> None:
+	with open("input", "r") as f:
+		data = [(xs[0], int(xs[1])) for xs in [l.split() for l in f.readlines()]]
+
+	snake = [Segment() for _ in range(SEGMENTS)]
+	head = snake[0]
+	tail = snake[-1]
+	locs: set[position] = set()
+
+	for d, c in data:
+		for _ in range(c):
+			match d:
+				case "U":
+					head.y += 1
+				case "D":
+					head.y -= 1
+				case "R":
+					head.x += 1
+				case "L":
+					head.x -= 1
+
+			for i, segment in enumerate(snake[1:]):
+				segment.track(snake[i].pos)
+
+			locs.add(tail.pos)
+
+	print(len(locs))
+
+
+if __name__ == "__main__":
+	main()
-- 
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