- 分类：Stack
- 时间复杂度: O(n)
- 空间复杂度: O(n)
71. 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"
代码：
class Solution:
def simplifyPath(self, path: 'str') -> 'str':
stack=[]
paths=path.split("/")
for p in paths:
if p=="..":
if stack!=[]:
stack.pop()
elif p!="." and p!="":
stack.append(p)
res="/"
if stack==[]:
return res
for s in stack:
res+=s+"/"
return res[:-1]
讨论：
1.这道题挺简单的，用stack方法就能完美解决
2.凡是遇到这种“路径类”的问题都用stack解，算是一个固定套路
