2024(6): solve part 1

The code is quite long lol. Also, the output is too verbose, but mwe!

2024/06/part1.py

@@ -1,15 +1,143 @@
+import numpy as np
+from enum import Enum
 
 
-def load_map(filename="input"):
-	with open(filename, "r") as fp:
-		data = fp.read
-
+'''
 idee:
 	sla ook het kleine voorbeeld op
-	lees data in
-	maak object "kaart"
-	maak op object
-		show() (prints map to screen)
 	guard_directions = ["^", ">", "v", "<"]
 	guard_path = [] # list of tuples (x, y)
+'''
 
+class Map:
+	directions = ["^", ">", "v", "<"]
+	#step_per_direction = [(0, -1), (1, 0), (0, 1), (-1, 0)]
+	step_per_direction = [(-1, 0), (0, 1), (1, 0), (0, -1)]
+
+	class Tiles(Enum):
+		BORDER = "+"
+		FREE = "."
+		OBSTACLE = "#"
+
+	def __init__(self):
+		self.trace = []
+		self.pos = None
+		self.direction = None
+
+	def next_pos(self):
+		"""
+		Returns next position given the state of this Map.
+		"""
+
+		next_pos = tuple([self.pos[i] + self.step_per_direction[self.directions.index(self.direction)][i] for i in range(len(self.pos))])
+		print("next_pos", next_pos)
+		return next_pos
+
+	def pos_in_map(self, pos):
+		"""
+		Returns whether pos is in the map.
+		"""
+		print("pos_in_map", pos) 
+		return pos[0] >= 0 and pos[0] < self.map.shape[0] \
+		   and pos[1] >= 0 and pos[0] < self.map.shape[1]
+
+	def look_ahead(self):
+		next_step = self.next_pos()
+		print("look_ahead.next_step", next_step)
+		if not self.pos_in_map(next_step):
+			return self.Tiles.BORDER
+		if self.map[*next_step] == "#":
+			return self.Tiles.OBSTACLE
+		if self.map[*next_step] == ".":
+			return self.Tiles.FREE
+
+	def next_direction(self, direction: str):
+		"""
+		Return the direction turning right given direction.
+		"""
+
+		assert direction in self.directions, "Invalid direction given"
+
+		if self.directions[-1] == direction:
+			return self.directions[0]
+		else:
+			return self.directions[self.directions.index(direction) + 1]
+
+	def seek_guard_in_map(self):
+		"""
+		Looks for the guard in the map and returns its position.
+
+		Will raise an exception if multiple or none are found.
+		"""
+		
+		guard_locations = []
+		for direction in self.directions:
+			guard_locations.extend(list(zip(*np.where(m.map == direction))))
+		return guard_locations
+	
+	def load_map(self, filename="input"):
+		"""
+		Reads a map from a file without verifying its contents.
+		"""
+
+		with open(filename, "r") as fp:
+			data = fp.read().splitlines()
+			chararray = np.array(data, dtype=str)\
+				.view("U1")\
+				.reshape((len(data), -1))
+		self.map = chararray
+
+		# Find the location of the guard in the map.
+		guards = self.seek_guard_in_map()
+		print(guards)
+		assert len(guards) == 1, "There should only be one guard in the map."
+
+		print(guards)
+		self.pos = guards[0]
+		self.trace.append(self.pos)
+		self.direction = m.map[self.pos]
+		# TODO: Use enum.
+		#self.map[self.pos] = self.Tiles.FREE
+		self.map[self.pos] = "."
+
+	def step(self):
+		"""
+		Take a step, turn or stop.
+		"""
+
+		next_tile = self.look_ahead()
+		print("step.next_tile", next_tile)
+
+		if next_tile == self.Tiles.FREE:
+			self.pos = self.next_pos()
+			self.trace.append(self.pos)
+			return True
+		elif next_tile == self.Tiles.OBSTACLE:
+			self.direction = self.next_direction(self.direction)
+			return True
+		elif next_tile == self.Tiles.BORDER:
+			return False
+
+		assert False, "Should not come here :')"	
+
+	def show(self):
+		"""Prints the current map to stdout."""
+
+		for i in range(len(self.map)):
+			for j in range(len(self.map[0])):
+				if self.pos == (i, j):
+					print(self.direction, end="")
+				else:
+					print(self.map[i][j], end="")
+			print()
+
+if __name__ == "__main__":
+	m = Map()
+	#m.load_map("testinput")
+	m.load_map("input")
+
+	while m.step():
+		print(m.pos, m.direction)
+		#m.show()
+	print(len(m.trace), m.trace)
+	print(len(set(m.trace)))

2024/06/testinput

@@ -0,0 +1,10 @@
+....#.....
+.........#
+..........
+..#.......
+.......#..
+..........
+.#..^.....
+........#.
+#.........
+......#...