Design an Advanced File System

Problem statement

Design a file system that allows the user to perform the following operations.

ls: Allows the users to list all the files and folders present in a directory path. The function should take in the directory path as input and return a list of all files and folder names present in this directory.

mkdir: Allows the users to create new directories. The function takes the directory name as the input and creates a new directory in the current directory.

pwd: Returns the path to the present working directory.

cd: Allows the users to enter a directory. The user cannot enter a file using this command.

touch: Allows the user to create a new file in the current directory. If a file with the same name already exists in the directory, it shows an error.

Example

Sample input