README.md

1233. Remove Sub-Folders from the Filesystem

Given a list of folders, remove all sub-folders in those folders and return in any order the folders after removing.

If a folder[i] is located within another folder[j], it is called a sub-folder of it.

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.

Example 1:

Input: folder = ["/a","/a/b","/c/d","/c/d/e","/c/f"]
Output: ["/a","/c/d","/c/f"]
Explanation: 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"]
Explanation: 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 character '/'
• Each folder name is unique.

Solutions (Rust)

1. Sort

impl Solution {
    pub fn remove_subfolders(folder: Vec<String>) -> Vec<String> {
        let mut folder = folder.into_iter().map(|s| s + "/").collect::<Vec<_>>();
        folder.sort_unstable();
        let mut ret = Vec::new();

        for f in folder {
            if ret.is_empty() || !f.starts_with(ret.last().unwrap()) {
                ret.push(f);
            }
        }
        ret.iter_mut().for_each(|s| {
            s.pop();
        });

        ret
    }
}