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119 lines
2.5 KiB
Python
119 lines
2.5 KiB
Python
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71. Simplify Path
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Difficulty: Medium
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https://leetcode.com/problems/simplify-path/
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──────────────────────────────────────────────────
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You are given an absolute path for a Unix-style file system, which
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always begins with a slash '/'. Your task is to transform this
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absolute path into its simplified canonical path.
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The rules of a Unix-style file system are as follows:
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• A single period '.' represents the current directory.
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• A double period '..' represents the previous/parent directory.
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• Multiple consecutive slashes such as '//' and '///' are treated as
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a single slash '/'.
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• Any sequence of periods that does not match the rules above should
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be treated as a valid directory or file name. For example, '...' and
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'....' are valid directory or file names.
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The simplified canonical path should follow these rules:
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• The path must start with a single slash '/'.
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• Directories within the path must be separated by exactly one slash
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'/'.
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• The path must not end with a slash '/', unless it is the root
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directory.
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• The path must not have any single or double periods ('.' and '..')
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used to denote current or parent directories.
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Return the simplified canonical path.
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Example 1:
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Input: path = "/home/"
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Output: "/home"
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Explanation:
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The trailing slash should be removed.
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Example 2:
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Input: path = "/home//foo/"
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Output: "/home/foo"
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Explanation:
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Multiple consecutive slashes are replaced by a single one.
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Example 3:
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Input: path = "/home/user/Documents/../Pictures"
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Output: "/home/user/Pictures"
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Explanation:
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A double period ".." refers to the directory up a level (the parent
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directory).
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Example 4:
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Input: path = "/../"
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Output: "/"
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Explanation:
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Going one level up from the root directory is not possible.
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Example 5:
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Input: path = "/.../a/../b/c/../d/./"
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Output: "/.../b/d"
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Explanation:
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"..." is a valid name for a directory in this problem.
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Constraints:
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• 1 <= path.length <= 3000
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• path consists of English letters, digits, period '.', slash '/' or
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'_'.
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• path is a valid absolute Unix path.
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"""
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class Solution:
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def simplifyPath(self, path: str) -> str:
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stack = []
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segments = [item for item in path.split("/") if item]
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for p in segments:
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if stack and p == "..":
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stack.pop()
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elif not stack and p == ".." or p == ".":
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continue
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else:
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stack.append(p)
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return "/" + "/".join(stack)
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