Python describe LeetCode 71. Simplified path

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subject

Give you a string path , Indicates a point to a file or directory Unix style Absolute path （ With '/' start ）, Please translate it into a more concise specification path .

stay Unix Style file system , One point （.） Represents the current directory itself ; Besides , Two points （..） Means to switch the directory to the next level （ Point to the parent directory ）; Both can be part of a complex relative path . Any number of consecutive slashes （ namely ,'//'） Are treated as a single slash '/' . For this problem , Points in any other format （ for example ,'...'） Are considered documents / Directory name .

Please note that , Back to Canonical path The following format must be followed ：

• Always with slash '/' start .
• There must be only one slash between two directory names '/' .
• Last directory name （ If there is ） You can't With '/' ending .
• Besides , The path contains only directories on the path from the root directory to the target file or directory （ namely , Not included '.' or '..'）.

Return the simplified Canonical path .

Example 1：

 Input ：path = "/home/"
Output ："/home"
explain ： Be careful , There is no slash after the last directory name .

Example 2：

 Input ：path = "/../"
Output ："/"
explain ： It's not feasible to go up from the root , Because the root directory is the highest level you can reach .

Example 3：

 Input ：path = "/home//foo/"
Output ："/home/foo"
explain ： In the canonical path , Multiple consecutive slashes need to be replaced with one slash .

Example 4：

 Input ：path = "/a/./b/../../c/"
Output ："/c"

Tips ：

• 1 <= path.length <= 3000
• path By the English letters , Numbers ,'.','/' or '_' form .
• path Is an effective Unix Style absolute path .

Their thinking

Utilization stack . If it is .. And there are elements in the stack , The top of the stack will pop up . If it is others, press the stack ,Python Can be used directly split Remove excess /, So don't worry

Python describe

class Solution:
def simplifyPath(self, path: str) -> str:
path = path.split('/')
stack = []
for item in path:
if item == '':
continue
if item == '..':
if len(stack) > 0:
stack.pop()
elif item != '.':
stack.append(item)
return "/"+'/'.join(stack)