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"""Day 12."""
import math
with open("input") as f:
instructions = f.read().rstrip().split("\n")
DIRECTIONS = ("N", "E", "S", "W")
CURRENT_DIRECTION = "E"
CORDS = {
"x": 0,
"y": 0,
}
WAYPOINT = {
'x': 10,
'y': 1,
}
def left(current_direction, degree):
idx = DIRECTIONS.index(current_direction) - (degree // 90)
return DIRECTIONS[idx % len(DIRECTIONS)]
def right(current_direction, degree):
idx = DIRECTIONS.index(current_direction) + (degree // 90)
return DIRECTIONS[idx % len(DIRECTIONS)]
def update_coords(direction, value):
if direction == "N":
CORDS["y"] += value
if direction == "E":
CORDS["x"] += value
if direction == "S":
CORDS["y"] -= value
if direction == "W":
CORDS["x"] -= value
for inst in instructions:
direction, value = inst[0], int(inst[1:])
if direction == "L":
CURRENT_DIRECTION = left(CURRENT_DIRECTION, value)
elif direction == "R":
CURRENT_DIRECTION = right(CURRENT_DIRECTION, value)
elif direction == "F":
update_coords(CURRENT_DIRECTION, value)
else:
update_coords(direction, value)
# Part 1
part_1 = abs(CORDS["x"]) + abs(CORDS["y"])
print(part_1)
assert part_1 == 882
# reset coords
CORDS = {
"x": 0,
"y": 0,
}
def update_waypoint(direction, value):
if direction == "N":
WAYPOINT["y"] += value
if direction == "E":
WAYPOINT["x"] += value
if direction == "S":
WAYPOINT["y"] -= value
if direction == "W":
WAYPOINT["x"] -= value
def clockwise(degrees):
"""rotate clockwise."""
x = WAYPOINT["x"]
y = WAYPOINT["y"]
rads = math.radians(degrees % 360)
return (
round(x * math.cos(rads) + y * math.sin(rads)),
round(-x * math.sin(rads) + y * math.cos(rads))
)
for inst in instructions:
direction, value = inst[0], int(inst[1:])
if direction == "L":
newx, newy = clockwise(360 - value)
WAYPOINT["x"] = newx
WAYPOINT["y"] = newy
elif direction == "R":
newx, newy = clockwise(value)
WAYPOINT["x"] = newx
WAYPOINT["y"] = newy
elif direction == "F":
CORDS["x"] += WAYPOINT["x"] * value
CORDS["y"] += WAYPOINT["y"] * value
else:
update_waypoint(direction, value)
part_2 = abs(CORDS["x"]) + abs(CORDS["y"])
assert part_2 == 28885
print(part_2)
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