Simplify Path Python Solution with Tests

lcpy gen -n 71   # by problem number
lcpy gen -s simplify_path   # by problem name

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Problem

• 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 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.

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Examples

Input: path = "/home/"
Output: "/home"

Input: path = "/home//foo/"
Output: "/home/foo"

Input: path = "/home/user/Documents/../Pictures"
Output: "/home/user/Pictures"

Input: path = "/../"
Output: "/"

Input: path = "/.../a/../b/c/../d/./"
Output: "/.../b/d"

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Constraints

• 1 <= path.length <= 3000
• path consists of English letters, digits, period '.', slash '/' or '_'.
• path is a valid absolute Unix path.

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Solution

class Solution:
    # Time: O(n)
    # Space: O(n)
    def simplify_path(self, path: str) -> str:
        stack: list[str] = []

        for part in path.split("/"):
            if part == "" or part == ".":
                continue
            if part == "..":
                if stack:
                    stack.pop()
            else:
                stack.append(part)

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

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Complexity

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