Print directory tree with indentation
Company: Uber
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
You are given a root directory of a filesystem represented as a tree. Each node is either a **directory** (can have children) or a **file** (no children). Print the directory structure starting from the root, using indentation to show depth.
### Output format
- Print one node per line.
- The root is printed with **no indentation**.
- For each depth level below the root, prefix the name with an indentation marker (for example: `⟶ `). Repeating the marker indicates deeper nesting.
Example formatting (depth shown by repeated markers):
```
dir
⟶ subdir1
⟶ ⟶ file1.ext
⟶ ⟶ subsubdir1
⟶ subdir2
⟶ ⟶ subsubdir2
⟶ ⟶ ⟶ file2.ext
```
### Requirements / assumptions
- You may assume the input is already a tree (no cycles).
- The children of a directory should be printed in the order they are provided.
### Task
Implement a function that, given the root node, prints (or returns as a list of strings) the directory tree in the required format.
Quick Answer: This question evaluates proficiency with representing and traversing hierarchical directory trees and producing depth-based formatted output, testing concepts such as tree traversal, recursion or iterative depth tracking, and string formatting for indentation.
Implement solution(root, indent_marker="-> ") that returns one line per node. root may be a dict with name and children or a [name, children] pair. Children must be emitted in the provided order.
Constraints
- The input is already a tree
- Files have no children
Examples
Input: ({'name': 'dir', 'children': [{'name': 'subdir1', 'children': [{'name': 'file1.ext', 'children': []}, {'name': 'subsubdir1', 'children': []}]}, {'name': 'subdir2', 'children': [{'name': 'subsubdir2', 'children': [{'name': 'file2.ext', 'children': []}]}]}]},)
Expected Output: ['dir', '-> subdir1', '-> -> file1.ext', '-> -> subsubdir1', '-> subdir2', '-> -> subsubdir2', '-> -> -> file2.ext']
Input: (['root', [['file', []]]], ' ')
Expected Output: ['root', ' file']
Hints
- Depth-first traversal naturally preserves child order.