71.SimplifyPath.py

"""
71
Given a string path, which is an absolute path (starting with a slash '/') to a file or directory in a Unix-style file system, convert it to the simplified canonical path.

In a Unix-style file system, a period '.' refers to the current directory, a double period '..' refers to the directory up a level, and any multiple consecutive slashes (i.e. '//') are treated as a single slash '/'. For this problem, any other format of periods such as '...' are treated as file/directory names.

The canonical path should have the following format:

The path starts with a single slash '/'.
Any two directories are separated by a single slash '/'.
The path does not end with a trailing '/'.
The path only contains the directories on the path from the root directory to the target file or directory (i.e., no period '.' or double period '..')

"""


class Solution:
    def simplifyPath(self, path):
        dir_stack = []
        path = path.split("/")
        for elem in path:
            if dir_stack and elem == "..":
                dir_stack.pop()
            elif elem not in [".", "", ".."]:
                dir_stack.append(elem)

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