Remove Sub-Folders from the Filesystem

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Problem Statement

Given a list of folders folder , return the folders after removing all sub-folders in those folders . You may return the answer in any order .

If a folder[i] is located within another folder[j] , it is called a sub-folder of it. A sub-folder of folder[j] must start with folder[j] , followed by a "/" . For example, "/a/b" is a sub-folder of "/a" , but "/b" is not a sub-folder of "/a/b/c" .

The format of a path is one or more concatenated strings of the form: '/' followed by one or more lowercase English letters.

For example, "/leetcode" and "/leetcode/problems" are valid paths while an empty string and "/" are not.

Examples

Example 1

Input: folder = ["/a","/a/b","/c/d","/c/d/e","/c/f"]
Output: ["/a","/c/d","/c/f"]
Folders "/a/b" is a subfolder of "/a" and "/c/d/e" is inside of folder "/c/d" in our filesystem.

Example 2

Input: folder = ["/a","/a/b/c","/a/b/d"]
Output: ["/a"]
Folders "/a/b/c" and "/a/b/d" will be removed because they are subfolders of "/a".

Example 3

Input: folder = ["/a/b/c","/a/b/ca","/a/b/d"]
Output: ["/a/b/c","/a/b/ca","/a/b/d"]

Constraints

1 <= folder.length <= 4 * 10 ^4

2 <= folder[i].length <= 100

folder[i] contains only lowercase letters and '/' .

folder[i] always starts with the character '/' .

Each folder name is unique .

🤔

Medium

Difficulty

Topic Info

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