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[LeetCode] 071. Simplify Path

Problem (Medium)

071. Simplify Path

Given an absolute path for a file (Unix-style), simplify it. Or in other words, convert it to the canonical path.

In a UNIX-style file system, a period . refers to the current directory. Furthermore, a double period .. moves the directory up a level. For more information, see: Absolute path vs relative path in Linux/Unix

Note that the returned canonical path must always begin with a slash /, and there must be only a single slash / between two directory names. The last directory name (if it exists) must not end with a trailing /. Also, the canonical path must be the shortest string representing the absolute path.

Example 1:

  • Input: "/home/"
  • Output: "/home"
  • Explanation: Note that there is no trailing slash after the last directory name.

Example 2:

  • Input: "/../"
  • Output: "/"
  • Explanation: Going one level up from the root directory is a no-op, as the root level is the highest level you can go.

Example 3:

  • Input: "/home//foo/"
  • Output: "/home/foo"
  • Explanation: In the canonical path, multiple consecutive slashes are replaced by a single one.

Example 4:

  • Input: "/a/./b/../../c/"
  • Output: "/c"

Example 5:

  • Input: "/a/../../b/../c//.//"
  • Output: "/c"

Example 6:

  • Input: "/a//b////c/d//././/.."
  • Output: "/a/b/c"

Approach 1: (My Solution - ‘split()’, ‘join’)

Idea

  • Use ‘split()’, ‘join’ to do the work.

Solution

class Solution1:
    def simplifyPath(self, path):
        """
        :type path: str
        :rtype: str
        """
        res = []
        l = path.split('/')
        for i in range(len(l)):
            if l[i] == '..':
                if len(res):
                    res.pop(-1)
                else:
                    continue
            elif l[i] in ['.', '']:
                continue
            else:
                res.append(l[i])
        return '/' + '/'.join(res)

Complexity

  • Time: $O(n)$
  • Space: $O(n)$



KF

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