2069\. Walking Robot Simulation II

Medium

A `width x height` grid is on an XY-plane with the **bottom-left** cell at `(0, 0)` and the **top-right** cell at `(width - 1, height - 1)`. The grid is aligned with the four cardinal directions (`"North"`, `"East"`, `"South"`, and `"West"`). A robot is **initially** at cell `(0, 0)` facing direction `"East"`.

The robot can be instructed to move for a specific number of **steps**. For each step, it does the following.

1.  Attempts to move **forward one** cell in the direction it is facing.
2.  If the cell the robot is **moving to** is **out of bounds**, the robot instead **turns** 90 degrees **counterclockwise** and retries the step.

After the robot finishes moving the number of steps required, it stops and awaits the next instruction.

Implement the `Robot` class:

*   `Robot(int width, int height)` Initializes the `width x height` grid with the robot at `(0, 0)` facing `"East"`.
*   `void step(int num)` Instructs the robot to move forward `num` steps.
*   `int[] getPos()` Returns the current cell the robot is at, as an array of length 2, `[x, y]`.
*   `String getDir()` Returns the current direction of the robot, `"North"`, `"East"`, `"South"`, or `"West"`.

**Example 1:**

![example-1](https://assets.leetcode.com/uploads/2021/10/09/example-1.png)

**Input**

["Robot", "step", "step", "getPos", "getDir", "step", "step", "step", "getPos", "getDir"]

[[6, 3], [2], [2], [], [], [2], [1], [4], [], []]

**Output:**

[null, null, null, [4, 0], "East", null, null, null, [1, 2], "West"]

**Explanation:**

    Robot robot = new Robot(6, 3); // Initialize the grid and the robot at (0, 0) facing East.
    robot.step(2);  // It moves two steps East to (2, 0), and faces East.
    robot.step(2);  // It moves two steps East to (4, 0), and faces East.
    robot.getPos(); // return [4, 0]
    robot.getDir(); // return "East"
    robot.step(2);  // It moves one step East to (5, 0), and faces East.
                    // Moving the next step East would be out of bounds, so it turns and faces North.
                    // Then, it moves one step North to (5, 1), and faces North.
    robot.step(1);  // It moves one step North to (5, 2), and faces North (not West).
    robot.step(4);  // Moving the next step North would be out of bounds, so it turns and faces West.
                    // Then, it moves four steps West to (1, 2), and faces West.
    robot.getPos(); // return [1, 2]
    robot.getDir(); // return "West" 

**Constraints:**

*   `2 <= width, height <= 100`
*   <code>1 <= num <= 10<sup>5</sup></code>
*   At most <code>10<sup>4</sup></code> calls **in total** will be made to `step`, `getPos`, and `getDir`.