# First Common Ancestor of Two Nodes in a Binary Tree | Aced 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/4538/binary-tree-first-common-ancestor Source observed: 2026-11-04T22:03:14.233Z Last checked: 2026-11-04T22:03:14.233+00:00 Indexed: 2026-11-05T07:51:26.48+00:00 --- # Find the first common ancestor of two nodes in a binary tree We provide this Aced (formerly Exponent) question as part of our interview-preparation library. It is classified under **Data Structures & Algorithms** and **Coding**, and is associated with the **Machine Learning Engineer** role and **Meta**. ## Question details - **Reported interviews:** 2 - **Reported last asked:** 10 months ago - **Community answers:** None contributed yet - **Actions:** Users can mark that they were asked this question, save it, and submit an answer. Submitting marks the question complete. Detailed company statistics require an upgrade: [Upgrade](https://www.aced.io/upgrade?src=questions). ## Interview experience We have **1 shared interview experience** associated with this question: - [Meta · 10 months ago](https://www.aced.io/experiences/meta-facebook-senior-machine-learning-engineer-interview-16fb62) — A candidate interviewed for **Software Engineer, Machine Learning at the L5 level**. The process included a recruiter screen, an online coding assessment, one live coding round, a second recruiter debrief call, and a final virtual onsite with three coding interviews, one behavioral interview, and one system design interview. The coding rounds were described as mostly classic algorithm questions. The system-design topic was a recommendation system for ranking locations in a feed for someone visiting a new city. The candidate felt the interviewers graded more leniently than the candidate would have graded themself. - Role: **Machine Learning Engineer · Senior / L5** ## Related questions - [Find the lowest common ancestor (LCA) of two nodes in a binary tree.](https://www.aced.io/questions/1156/lowest-common-ancestor-binary-tree) - [Find the common ancestors in a tree.](https://www.aced.io/questions/3443/find-common-ancestors-tree) - [Print the top view of nodes in a binary tree.](https://www.aced.io/questions/5570/top-view-nodes-binary-tree) ## Related courses ### [Machine Learning Engineer Interview Prep](https://www.aced.io/courses/ml-engineer) ![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) We help candidates prepare for machine-learning roles at Meta, Google, Amazon, Apple, Microsoft, Nvidia, and other top companies through mock interviews, frameworks, and advice from senior candidates. 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