'''
On an infinite plane, a robot initially stands at (0, 0) and faces north. Note that:

The north direction is the positive direction of the y-axis.
The south direction is the negative direction of the y-axis.
The east direction is the positive direction of the x-axis.
The west direction is the negative direction of the x-axis.
The robot can receive one of three instructions:

"G": go straight 1 unit.
"L": turn 90 degrees to the left (i.e., anti-clockwise direction).
"R": turn 90 degrees to the right (i.e., clockwise direction).
The robot performs the instructions given in order, and repeats them forever.

Return true if and only if there exists a circle in the plane such that the robot never leaves the circle.

 

Example 1:

Input: instructions = "GGLLGG"
Output: true
Explanation: The robot is initially at (0, 0) facing the north direction.
"G": move one step. Position: (0, 1). Direction: North.
"G": move one step. Position: (0, 2). Direction: North.
"L": turn 90 degrees anti-clockwise. Position: (0, 2). Direction: West.
"L": turn 90 degrees anti-clockwise. Position: (0, 2). Direction: South.
"G": move one step. Position: (0, 1). Direction: South.
"G": move one step. Position: (0, 0). Direction: South.
Repeating the instructions, the robot goes into the cycle: (0, 0) --> (0, 1) --> (0, 2) --> (0, 1) --> (0, 0).
Based on that, we return true.
Example 2:

Input: instructions = "GG"
Output: false
Explanation: The robot is initially at (0, 0) facing the north direction.
"G": move one step. Position: (0, 1). Direction: North.
"G": move one step. Position: (0, 2). Direction: North.
Repeating the instructions, keeps advancing in the north direction and does not go into cycles.
Based on that, we return false.
Example 3:

Input: instructions = "GL"
Output: true
Explanation: The robot is initially at (0, 0) facing the north direction.
"G": move one step. Position: (0, 1). Direction: North.
"L": turn 90 degrees anti-clockwise. Position: (0, 1). Direction: West.
"G": move one step. Position: (-1, 1). Direction: West.
"L": turn 90 degrees anti-clockwise. Position: (-1, 1). Direction: South.
"G": move one step. Position: (-1, 0). Direction: South.
"L": turn 90 degrees anti-clockwise. Position: (-1, 0). Direction: East.
"G": move one step. Position: (0, 0). Direction: East.
"L": turn 90 degrees anti-clockwise. Position: (0, 0). Direction: North.
Repeating the instructions, the robot goes into the cycle: (0, 0) --> (0, 1) --> (-1, 1) --> (-1, 0) --> (0, 0).
Based on that, we return true.
 

Constraints:

1 <= instructions.length <= 100
instructions[i] is 'G', 'L' or, 'R'.
'''
import unittest


class Solution:
    def isRobotBounded(self, instructions: str) -> bool:
        left = (0, -1)
        right = (0, 1)
        up = (-1, 0)
        down = (1, 0)
        left_map = {
           left: down,
           right: up,
           up: left,
           down: right 
        }
        right_map = {
            left: up,
            right: down,
            up: right,
            down: left
        }
        
        res = [0, 0]
        direction = up
        for instruct in instructions:
            if instruct == "G":
                res[0] += direction[0]
                res[1] += direction[1]
            elif instruct == "L":
                direction = left_map[direction]
            elif instruct == "R":
                direction = right_map[direction]
        return direction != up or res == [0, 0]


class TestSolution(unittest.TestCase):

    def test_case(self):
        examples = (
            (("GGLLGG",), True),
            (("GG",), False),
            (("GL",), True),
        )
        for first, second in examples:
            self.assert_function(first, second)

    def assert_function(self, first, second):
        self.assertEqual(Solution().isRobotBounded(*first), second,
                         msg="first: {}; second: {}".format(first, second))


unittest.main()
