Meta / Amazon / Google Interview Question — LeetCode 1233

In this post, we are going to discuss leetcode 1233 — Remove Sub-Folders from the Filesystem, which is asked in Google, Meta, and Amazon interviews.

Problem Analysis

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.

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"]

My Thinking Process

This is an array and string problem. I cannot find a way to translate it to some specific…