def part_2(cmds):
ship = Vector(0, 0)
waypoint = Vector(10, 1)
for dir, steps in cmds:
if dir == "F":
ship += waypoint * steps
elif dir in NESW_VEC:
waypoint += NESW_VEC[dir] * steps
elif dir == "R":
waypoint = waypoint.rotate_degree(steps)
elif dir == "L":
waypoint = waypoint.rotate_degree(-steps)
else:
raise Exception(f"Unknown instruction {(dir, steps)}")
return abs(ship.x) + abs(ship.y)
def test_rotation():
vec = Vector(1, 2)
assert Vector(2, -1) == vec.rotate_degree(90)
assert Vector(-1, -2) == vec.rotate_degree(180)
assert Vector(-2, 1) == vec.rotate_degree(-90)