## Problem You have a permission tree where each node has an `id`, a `parent_id`, and an `access_level` (0=public, 1=restricted, 2=private). A user has a clearance level. A node is accessible if `user_clearance >= node.access_level` AND all ancestors are accessible. Given a target node and a user clearance, find the topmost accessible ancestor — the highest node in the path from root to target that the user can access. If the root itself is accessible, return the root. ```python def topmost_accessible( nodes: dict[str, dict], # id -> {parent_id, access_level} target_id: str, user_clearance: int ) -> str | None: ... ``` ``` Tree: root(0) -> dept(1) -> team(2) -> doc(2) User clearance = 1 Path root->dept->team->doc Accessible: root(ok), dept(ok), team(fail), doc(fail) Topmost accessible = "dept" ``` ## Follow-ups 1. If the root itself is inaccessible, what do you return? 2. How does your solution change if permission inheritance can be broken (a public node under a private one)? 3. For a tree with 1 million nodes, you need to answer 10,000 topmost-accessible queries per second. How do you precompute or cache? 4. Extend to support group-based permissions (user belongs to groups; a node grants access to a group). How does this change the lookup?

InterviewDB Question · USA

Topmost Accessible Node: Find the Highest Ancestor a User Can Read Given Permission Rules

phone

Question Details

Problem You have a permission tree where each node has an id, a parent_id, and an access_level (0=public, 1=restricted, 2=private). A user has a clearance level. A node is accessible if user_clearance >= node.access_level AND all ancestors are accessible. Given a target node and a user clearance, find the topmost accessible ancestor — the highest node in the path from root to target that the user can access. If the root itself is accessible, return the root. Follow-ups If the root itself is inac…

Full Details

🔒

Unlock all Figma questions

Full insider details, leaked discussions, and candidate experiences.

Get full access — $100 a year, unlimited access

About This Question

This is a reported interview question from a figma interview during the phone round.

It covers the following topics: Coding, Onsite, Phone .

Topics

Coding Onsite Phone

Topmost Accessible Node: Find the Highest Ancestor a User Can Read Given Permission Rules

Question Details

Full Details

About This Question

Topics

More Figma Interview Questions