71.Simplify Path

tags: `Medium`,`String`,`Stack`

題目描述

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 '..')

Return the simplified canonical path.

範例

Example 1:

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

Example 2:

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

Constraints:

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

解答

Python















class Solution:
    def simplifyPath(self, path: str) -> str:
        stack = []
        path_list = path.split("/")

        for p in path_list:
            if not p or p == '.':
                continue
            elif p == '..':
                if stack:
                    stack.pop()
            else:
                stack.append(p)

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

Ron ChenWed, Apr 12, 2023


















class Solution:
    def simplifyPath(self, path: str) -> str:
        path = path.split('/')
        s = []
        for p in path:
            if p == '':
                continue
            elif p == '.':
                continue
            elif p == '..':
                for i in range(min(len(s), 1)):
                    s.pop()
            else:
                s.append(p)

        return '/'+'/'.join(s)

Javascript













function simplifyPath(path) {
  const stack = [];
  const dirs = path.split('/');
  for (const dir of dirs) {
    if (dir === '..') {
      stack.pop();
    } else if (dir !== '.' && dir !== '') {
      stack.push(dir);
    }
  }

  return '/' + stack.join('/');
}

MarsgoatWed, Apr 12, 2023

TypeScript


















function simplifyPath(path: string): string {
  const stack: string[] = [];
  const pathArr = path.split('/');

  const emptyString = '';
  const onePeriod = '.';
  const doublePeriod = '..';

  pathArr.forEach((d) => {
    if (d === doublePeriod) {
      stack.pop();
    } else if (d !== onePeriod && d !== emptyString) {
      stack.push(d);
    }
  });

  return '/' + stack.join('/');
}

SheepThu, Apr 13, 2023

Reference

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