71. 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

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.

Solution

class Solution:
    def simplifyPath(self, path: str) -> str:
        stack = []
        segments = [item for item in path.split("/") if item]

        for p in segments:
            if stack and p == "..":
                stack.pop()
            elif not stack and p == ".." or p == ".":
                continue
            else:
                stack.append(p)

        return "/" + "/".join(stack)