# Find the common ancestors in a tree. Aced (formerly Exponent) publishes a public search API over its indexed pages; the guide is at https://www.aced.io/agents/agent-access. Source: https://www.aced.io/questions/3443/find-common-ancestors-tree Source observed: 2026-11-05T00:19:31.582Z Last checked: 2026-11-05T00:19:31.582+00:00 Indexed: 2026-11-06T01:34:58.626+00:00 --- # Find the common ancestors in a tree. This is an Aced (formerly Exponent) **Data Structures & Algorithms** and **Coding** interview question for a **Machine Learning Engineer** role at **Meta**. The task is to find the common ancestors in a tree. ## Access and membership The video answer requires an upgrade. Membership includes: - 100+ expert answer videos - Access to all courses - Peer-to-peer practice - Private Discord community - Full question database [Upgrade now](https://www.aced.io/upgrade?src=questions) The question shows **2 interviews** and was **last asked 9 months ago**. No community answers have been contributed yet. You can log in or sign up to submit an answer. ## Interview experience **Meta · 9 months ago** — shared as an interview experience for a **Machine Learning Engineer · Senior / L5** role: > “This was my second time going through the same Meta MLE process, and compared to the prior year the big changes were a written portal pre-screen and the new AI-enabled coding round. A sourcer reached out by email, I filled out the questionnaire, then I did a 45-minute coding screen with two LeetCode-style questions before getting the full loop. I split the loop across four days, one round per day: coding, AI-enabled debugging/coding, behavioral, and an ML design round on a TikTok-style recommendation system. The coding felt very standard Meta to me, but the AI round was the distinctive one because I had to debug an unfamiliar codebase, run tests intelligently, and use an LLM without blindly trusting it.” [Read the Meta interview experience](https://www.aced.io/experiences/meta-facebook-senior-machine-learning-engineer-interview-8719a7) ## Related questions - [Find the first common ancestor of two nodes in a binary tree.](https://www.aced.io/questions/4538/binary-tree-first-common-ancestor) - [Find the lowest common ancestor (LCA) of two nodes in a binary tree.](https://www.aced.io/questions/1156/lowest-common-ancestor-binary-tree) ## Related courses ![Machine Learning Engineer Interview Prep](https://images.ctfassets.net/x78yjrjc11pq/6UfkHxUyLQVfDHSfLNQtWa/1be1539a65b4f6f15201f5b573c0a578/ML_Engineer_Interview_Prep_Course.jpeg?w=800&h=800&fm=webp&q=75) ### [Machine Learning Engineer Interview Prep](https://www.aced.io/courses/ml-engineer) Prepare for machine-learning roles at Meta, Google, Amazon, Apple, Microsoft, Nvidia, and other companies through mock interviews, frameworks, and advice from senior candidates. Topics include ML system design, core concepts, coding, behavioral interviews, and more. ![Behavioral Interviews: A Practical Guide for Engineers](https://images.ctfassets.net/x78yjrjc11pq/47qcoHjzFZXE37GoacedkB/9d8e3f4910d8b06b21e76745cd9cbff3/AdobeStock_1142146335.jpeg?w=800&h=800&fm=webp&q=75) ### [Behavioral Interviews: A Practical Guide for Engineers](https://www.aced.io/courses/eng-behavioral) Prepare for senior-plus behavioral interviews at FAANG and Tier-1 companies with material made with staff and principal engineers from Meta, Netflix, Google, and more. Focus on avoiding downleveling, elevating past projects, and communicating naturally. ## Your answer Sign in or sign up to answer the question, then submit to mark it complete. --- [Read this page’s summary](https://www.aced.io/agents/api/public/v1/page-tldr?url=https%3A%2F%2Fwww.aced.io%2Fquestions%2F3443%2Ffind-common-ancestors-tree&trace=t_679ff9ab98f3) ## Ask a follow-up about this page Need a more specific answer? Ask the exact question you have. It returns a fresh, cited answer from Aced (formerly Exponent)’s knowledge base. No account or API key required. Open this URL with your own question, URL-encoded. Include your question in q. All research inputs are optional; no account or setup. `GET https://www.aced.io/agents/agent/faq?q={question}&trace=t_679ff9ab98f3` [Tool guide and examples](https://www.aced.io/agents/agent-access) · [OpenAPI](https://www.aced.io/agents/api/public/v1/openapi.json) · [Page TLDR form](https://www.aced.io/agents/agent-tools/page-tldr?url=https%3A%2F%2Fwww.aced.io%2Fquestions%2F3443%2Ffind-common-ancestors-tree). Opening a form does not execute a tool.