advent-of-code/2020/day12_navigation.py

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import enum
import functools
def main(filename: str, expected_part_1: int = None, expected_part_2: int = None):
print(f"\n+ Running on {filename}")
with open(filename) as f:
instructions = f.read().strip().split("\n")
counter_part_1 = solve_part_1(instructions)
print(f"1. Found {counter_part_1}")
if expected_part_1:
assert expected_part_1 == counter_part_1
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counter_part_2 = solve_part_2(instructions)
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print(f"2. Found {counter_part_2}")
if expected_part_2:
assert expected_part_2 == counter_part_2
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def solve_part_1(instructions: list[str]):
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ship = ShipPart1()
ship.apply_instructions(instructions)
return ship.distance_from_origin
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def solve_part_2(instructions: list[str]):
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ship = ShipPart2()
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ship.apply_instructions(instructions)
return ship.distance_from_origin
class Ship:
def __init__(self):
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self.vertical = 0
self.horizontal = 0
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def apply_instructions(self, instructions):
for instruction in instructions:
self.apply_instruction(instruction)
@property
def distance_from_origin(self):
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return abs(self.vertical) + abs(self.horizontal)
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@staticmethod
def parse_instruction(instruction):
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letter = instruction[0]
value = int(instruction[1:])
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return letter, value
def apply_instruction(self, instruction):
raise NotImplementedError
class ShipPart1(Ship):
def __init__(self):
super().__init__()
self.facing = Direction.EAST
def apply_instruction(self, instruction):
letter, value = self.parse_instruction(instruction)
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if letter in Direction.values():
direction = Direction(letter)
self.move(direction, value)
elif letter == "F":
self.move(self.facing, value)
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else:
self.turn(letter, value)
def move(self, direction: "Direction", value: int):
if direction == Direction.NORTH:
self.vertical += value
elif direction == Direction.SOUTH:
self.vertical -= value
elif direction == Direction.EAST:
self.horizontal += value
else:
self.horizontal -= value
def turn(self, letter, value):
if letter == "L":
value = -value
self.facing = self.facing.turn(value)
class ShipPart2(Ship):
def __init__(self):
super().__init__()
self.waypoint = (10, 1) # 10 units east, 1 unit north
def apply_instruction(self, instruction):
letter, value = self.parse_instruction(instruction)
if letter in Direction.values():
direction = Direction(letter)
self.move_waypoint(direction, value)
elif letter == "F":
self.move_to_waypoint(value)
else:
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if letter == "L":
value = -value
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self.turn_waypoint(value)
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def move_waypoint(self, direction: "Direction", value: int):
if direction in [Direction.NORTH, Direction.SOUTH]:
if direction == Direction.SOUTH:
value = -value
self.waypoint = self.waypoint[0], self.waypoint[1] + value
else:
if direction == Direction.WEST:
value = -value
self.waypoint = self.waypoint[0] + value, self.waypoint[1]
def move_to_waypoint(self, number_of_times: int):
horizontal = self.waypoint[0] * number_of_times
self.horizontal += horizontal
vertical = self.waypoint[1] * number_of_times
self.vertical += vertical
def turn_waypoint(self, angle: int):
if angle == 0:
return
horizontal = self.waypoint[0]
vertical = self.waypoint[1]
top_right_quadrant = vertical >= 0 and horizontal >= 0
bottom_right_quadrant = vertical < 0 and horizontal >= 0
bottom_left_quadrant = vertical < 0 and horizontal < 0
if angle < 0:
if top_right_quadrant:
self.waypoint = -abs(vertical), abs(horizontal)
elif bottom_right_quadrant:
self.waypoint = abs(vertical), abs(horizontal)
elif bottom_left_quadrant:
self.waypoint = abs(vertical), -abs(horizontal)
else:
self.waypoint = -abs(vertical), -abs(horizontal)
return self.turn_waypoint(angle + 90)
else:
if top_right_quadrant:
self.waypoint = abs(vertical), -abs(horizontal)
elif bottom_right_quadrant:
self.waypoint = -abs(vertical), -abs(horizontal)
elif bottom_left_quadrant:
self.waypoint = -abs(vertical), abs(horizontal)
else:
self.waypoint = abs(vertical), abs(horizontal)
return self.turn_waypoint(angle - 90)
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class Direction(enum.Enum):
NORTH = "N"
SOUTH = "S"
EAST = "E"
WEST = "W"
@staticmethod
@functools.lru_cache(maxsize=1)
def values():
return {e.value for e in Direction}
def turn(self, angle):
if angle == 0:
return self
if self == Direction.NORTH:
if angle > 0:
return Direction.EAST.turn(angle - 90)
else:
return Direction.WEST.turn(angle + 90)
if self == Direction.SOUTH:
if angle > 0:
return Direction.WEST.turn(angle - 90)
else:
return Direction.EAST.turn(angle + 90)
if self == Direction.EAST:
if angle > 0:
return Direction.SOUTH.turn(angle - 90)
else:
return Direction.NORTH.turn(angle + 90)
if self == Direction.WEST:
if angle > 0:
return Direction.NORTH.turn(angle - 90)
else:
return Direction.SOUTH.turn(angle + 90)
if __name__ == "__main__":
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main("inputs/day12-test1", 25, 286)
main("inputs/day12-test2", None, 202)
main("inputs/day12", 1177, 46530)