71. 简化路径
71. 简化路径
题目
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.
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.
题目大意
给你一个字符串 path
,表示指向某一文件或目录的 Unix 风格 绝对路径 (以 '/'
开头),请你将其转化为更加简洁的规范路径。
在 Unix 风格的文件系统中,一个点(.
)表示当前目录本身;此外,两个点 (..
) 表示将目录切换到上一级(指向父目录);两者都可以是复杂相对路径的组成部分。任意多个连续的斜杠(即,'//'
)都被视为单个斜杠 '/'
。 对于此问题,任何其他格式的点(例如,'...'
)均被视为文件/目录名称。
请注意,返回的 规范路径 必须遵循下述格式:
- 始终以斜杠
'/'
开头。 - 两个目录名之间必须只有一个斜杠
'/'
。 - 最后一个目录名(如果存在)不能 以
'/'
结尾。 - 此外,路径仅包含从根目录到目标文件或目录的路径上的目录(即,不含
'.'
或'..'
)。
返回简化后得到的 规范路径 。
解题思路
这道题利用栈先进后出的特性处理上级目录 '..'
,最后组装化简后的路径即可。
代码
/**
* @param {string} path
* @return {string}
*/
var simplifyPath = function (path) {
const arr = path.split('/');
let stack = [];
for (let i of arr) {
if (i == '' || i == '.') {
continue;
} else if (i == '..') {
if (stack.length > 0) stack.pop();
} else {
stack.push(i);
}
}
return '/' + stack.join('/');
};