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[71] Simplify Path

https://leetcode.com/problems/simplify-path/description/

algorithms
Medium (27.45%)
Source Code: 71.simplify-path.py
Total Accepted: 146.4K
Total Submissions: 513.9K
Testcase Example: '"/home/"'

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"

python

class Solution(object):
    def simplifyPath(self, path):
        """
        :type path: str
        :rtype: str
        """
        newpath = path.replace('//', '/').replace('..', '*')
        while newpath != path:
            path = newpath
            newpath = newpath.replace('//', '/').replace('..', '*')

        path = path.strip('/')

        path = path.split('/')

        result = []
        for p in path:
            if p == '.':
                continue
            elif p == '*':
                if result:
                    result.pop(-1)
            else:
                result.append(p)

        ret = '/' + '/'.join(result)
        ret = ret.replace('*', '..')
        return ret