Print Directory with Indentation

Given a root directory, implement a program to print the directory tree in the following format: dir subdir1 file1.ext subsubdir1 subdir2 subsubdir2 file2.ext Requirements: Handle arbitrary depth of nesting. Only print the directory structure; no need to read from actual filesystem. Assume the input data is correctly formatted with directories and files. Input: A multi-line string representing the directory structure, where each line is a directory or file, with levels indicated by tabs. Output: Print the directory tree in the specified format. Example Input dir subdir1 file1.ext subsubdir1 subdir2 subsubdir2 file2.ext