Simplify Path

You are given an _absolute_ path for a Unix-style file system, which always begins with a slash `'/'`. Your task is to transform this absolute path into its **simplified canonical path**. The _rules_ of a Unix-style file system are as follows: - A single period `'.'` represents the current directory. - A double period `'..'` represents the previous/parent directory. - Multiple consecutive slashes such as `'//'` and `'///'` are treated as a single slash `'/'`. - Any sequence of periods that does **not match** the rules above should be treated as a **valid directory or** **file ****name**. For example, `'...' `and `'....'` are valid directory or file names. The simplified canonical path should follow these _rules_: - The path must start with a single slash `'/'`. - Directories within the path must be separated by exactly one slash `'/'`. - The path must not end with a slash `'/'`, unless it is the root directory. - The path must not have any single or double periods (`'.'` and `'..'`) used to denote current or parent directories. Return the **simplified canonical path**.   **Example 1:** **Input:** path = "/home/" **Output:** "/home" **Explanation:** The trailing slash should be removed. **Example 2:** **Input:** path = "/home//foo/" **Output:** "/home/foo" **Explanation:** Multiple consecutive slashes are replaced by a single one. **Example 3:** **Input:** path = "/home/user/Documents/../Pictures" **Output:** "/home/user/Pictures" **Explanation:** A double period `".."` refers to the directory up a level (the parent directory). **Example 4:** **Input:** path = "/../" **Output:** "/" **Explanation:** Going one level up from the root directory is not possible. **Example 5:** **Input:** path = "/.../a/../b/c/../d/./" **Output:** "/.../b/d" **Explanation:** `"..."` is a valid name for a directory in this problem.   **Constraints:** - `1 <= path.length <= 3000` - `path` consists of English letters, digits, period `'.'`, slash `'/'` or `'_'`. - `path` is a valid absolute Unix path.