package q1041

type Dir int8

const (
	UP Dir = iota
	RIGHT
	DOWN
	LEFT
)

func (d Dir) TurnL() Dir { return (d + 3) % 4 }
func (d Dir) TurnR() Dir { return (d + 1) % 4 }

var vects = [][2]int{{0, -1}, {1, 0}, {0, 1}, {-1, 0}}

func isRobotBounded(instructions string) bool {
	x, y, d := 0, 0, UP

	for range 4 {
		for i := range len(instructions) {
			switch instructions[i] {
			case 'G':
				x += vects[d][0]
				y += vects[d][1]
			case 'L':
				d = d.TurnL()
			case 'R':
				d = d.TurnR()
			}
		}

		if x == 0 && y == 0 && d == UP {
			return true
		}
	}
	return false
}

var _ = isRobotBounded