ByteDance Interview Questions — Page 12

ByteDance·Software Engineer·Technical Phone Screen

May 2026

Bytedance SRE interview, coding round. Not much to report, it was pretty quick and straightforward.

Given an array of integers, move all zeroes to the end while maintaining the relative order of the non-zero elements.

“Only had about 15 minutes left at this point so I just pushed through it fast.”

ByteDance·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Behavioral round at Bytedance for a software engineering role. Short session, maybe 15 minutes, focused almost entirely on project ownership and complexity. Nothing too wild but the follow-up questions on the first one caught me a bit off guard.

Walk me through your most challenging project. What made it difficult, what decisions did you own, what obstacles did you hit, and what was the outcome?
Have you ever led a project as the primary owner rather than just a contributor? Describe the scope, your responsibilities, how you worked with stakeholders, and the result.

“I had a story prepped but the follow-ups went deeper than I expected.”

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ByteDance·Backend Engineer·Technical Phone Screen

May 2026

Bytedance backend round, one algorithmic question that looked simple on the surface but had a real gotcha in the space constraint. Managed to get through it but spent too long second-guessing myself on the operator precedence handling.

Given a string representing a valid arithmetic expression with non-negative integers and +, -, *, / operators separated by spaces (no parentheses), evaluate it and return the integer result. Integer division should truncate toward zero. Can you do it in O(n) time?

“My first instinct was stack, which works fine, but they pushed back asking if I could do it with O(1) space.”

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ByteDance·Software Engineer·Onsite - System Design / Architecture

May 2026

System design round at Bytedance focused entirely on building a metrics collection and monitoring platform from scratch, think Prometheus or Datadog scale. Pretty intense scope for a single session.

Design a large-scale metrics collection and monitoring system similar to Prometheus or Datadog. Walk through functional requirements, non-functional requirements, and the overall architecture.

“This is basically a full platform design in one question.”

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ByteDance·Software Engineer·Technical Phone Screen

May 2026

Bytedance software engineer interview with four coding problems back to back. Mix of string manipulation, combinatorics, and a date math problem that felt out of place. Nothing too wild but the subset questions with duplicates tripped me up a bit.

Given a string of words with potentially multiple spaces between them and leading or trailing spaces, reverse the order of the words and return the result with exactly one space between each word and no extra whitespace.
Given an array of distinct integers, return all possible subsets including the empty set.
Same as the previous subsets problem, but the input array may contain duplicate values. Return only unique subsets with no repeats in the output.
Given two date strings in YYYY-MM-DD format, return the absolute number of days between them.

“Pretty standard but the follow-up is what they actually care about.”

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ByteDance·Software Engineer·Hiring Manager Screen

May 2026

Second round with the hiring manager at Bytedance for a software engineer role, conducted in Chinese. It was a technical deep dive focused on an AI project, and it went pretty smoothly after a lot of prep beforehand.

Walk me through an AI project you've worked on in depth.

“All that drilling paid off here.”

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ByteDance·Software Engineer·Technical Phone Screen

May 2026

First-round at Bytedance for a Software Engineer role that packed three very different things into one session: resume walkthrough, ML fundamentals, and a live coding problem. Time management across all three is the real challenge nobody warns you about.

Walk me through your past projects, including the technical decisions you made and what impact they had.
Explain how Transformers work, including details on the architecture and design choices.
What are the tradeoffs between different optimizers, and when would you choose one over another?
How do regularization techniques work, and what problems are they solving?
Solve a medium-difficulty coding problem live.

“This part went longer than I expected.”

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ByteDance·Data Scientist·Technical Phone Screen

May 2026

Bytedance data scientist interview, all conceptual ML questions, no coding. The depth they expected was pretty serious for a DS role, felt more like an MLE loop honestly. Six questions across deployment, retrieval, regularization, and RL fine-tuning.

Under tight GPU compute and memory constraints, how would you deploy a multimodal model for video retrieval or ranking? Walk through architecture choices, compression, batching, caching, and how you'd balance latency, throughput, quality, and cost.
Given that captions and video embeddings are already precomputed, how would you speed up online video retrieval? Cover indexing, approximate nearest neighbor search, hybrid retrieval combining text and vector signals, reranking, memory footprint, and keeping the index fresh.
What is overfitting, how do you detect it, and what are your go-to mitigation strategies in deep learning?
Explain how Dropout works mathematically and why inverted Dropout is used to keep activation magnitudes consistent between training and inference.
Compare BatchNorm, LayerNorm, GroupNorm, and RMSNorm. When would you use each, and how are running statistics handled at inference time for the ones that need them?
How is reinforcement learning used in LLM post-training? Describe the full pipeline including supervised fine-tuning, preference data collection, reward modeling, policy optimization, KL regularization, and where things typically go wrong.

“This one took a while to unpack.”

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ByteDance·Machine Learning Engineer·Technical Phone Screen

May 2026

Bytedance ML Engineer interview with a pretty gnarly algorithm problem. One question, prefix sum style, and they made it clear that brute force wasn't going to cut it.

Given an integer array and two integers (modulo and target), count contiguous subarrays where the number of 'special' elements (those whose value mod modulo equals target) has a remainder of target when divided by modulo. Return the count as a 64-bit integer. An O(n^2) solution is not acceptable.

“I stared at this for a solid minute before realizing it's a prefix sum + frequency map problem.”

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ByteDance·Machine Learning Engineer·Technical Phone Screen

May 2026

Bytedance ML engineer interview with a meaty NLP design question around semantic similarity. One question but it had a lot of surface area to cover.

Given two text inputs, design and implement a method to compute their semantic similarity. Walk through preprocessing, how you'd generate embeddings, how cosine similarity works, edge case handling, and the trade-offs between sentence-level encoders versus averaging word embeddings.

“This question sprawls more than it looks.”

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