In today's interview, I want to talk about a recent interview with a trainee. ByteDance 2026 Summer SDE Intern Electric Interview (VO round). At the beginning, we all thought that the US base position would be more emphasized on coding + project, but in the end, we were directly "educated" by this interview - the degree of solidity of the eight stocks completely determines the upper limit of the interview.
This round of 60min has a very typical structure of electric surfaces, divided into three parts:
1️⃣ Coding Hands-on (30min)
2️⃣ Project Deep Excavation (15min)
3️⃣ Computer Basics (15min)
I'm going to break down the whole scene in order. bytedance interview process The pacing, test points, and preparation focus.
I. Coding Section: LeetCode 1209 Remove All Adjacent Duplicates in String II
This question is in the bytedance coding interview questions It occurs very frequently in the, and examines logical clarity and the ability to apply the stack. The meaning of the question is:
Given a string s and an integer k, keep removing the same character k times in a row until you can't remove any more.
Example:
Input: s = "deeedbbcccbdaa", k = 3
Output: "aa"
The topic requirements are not difficult, it's all about what the interviewer sees in you:
- Is it possible to quickly model with stack
- Can you correctly handle multi-layer nested deletions
- Whether time complexity and memory overhead are considered
The core idea that trainees implement in Python is:
Use a stack to store the characters and the number of occurrences, and each time you push, if the number of occurrences == k, then pop it. At the end, we can put the string back together again.
def removeDuplicates(s: str, k: int) -> str.
stack = []
for ch in s.
if stack and stack[-1][0] == ch.
stack[-1][1] += 1
if stack[-1][1] == k.
stack.pop()
else: stack.append([ch])
stack.append([ch, 1])
return ''.join(ch * cnt for ch, cnt in stack)
The interviewer's follow-up was, "How can you optimize memory usage if the strings are very long (e.g., millions)?"
The answer focuses on the fact that the space complexity O(n) is already a theoretical lower bound, unless the topic allows in-place modifications or stream inputs.
On the whole, this question was a solid win. The interviewer is more concerned about your ability to think logically and express yourself, and the trainee verbalizes the significance of each judgment while writing, which adds up to a lot of points.
II. Project Deep Dive: Amazon Internship Program
The project part is "half talking about technology and half talking about system design", the interviewer obviously wants to judge the candidate's system understanding and ownership through the project.
The participant briefly describes a service optimization project he did as an intern at Amazon about improving the response time of internal APIs (latency optimization).
The interviewer followed up with three questions:
- How are you locating performance bottlenecks?
- What profiling tools are used in the optimization process?
- How are the results verified?
Here's a word of advice: ByteDance interviewers are less interested in hearing high-level narratives (e.g., "We did system optimization") and more interested in hearing details such as:
- "We use CloudWatch + FlameGraph to analyze CPU hotspot"
- "Found that 40% time was consumed in JSON parsing, so switched to Protocol Buffers"
- "Before and after deployment we verified latency from 200ms → 120ms using A/B testing"
Our suggested answer is to use the STAR structure (situation-task-action-result) to talk about the project, but focus on Action details and Result quantifiable, so that it looks more professional.
III. Eight-unit component (computer-based)
This paragraph was the key point of difference in the whole interview. The trainee mainly prepared for coding + behavior before and didn't spend much time on CS fundamentals, and as a result, he was asked very detailed questions here.
Exam points include:
1. Hashtable implementation
Question: "Can you tell us how HashTable is implemented? What happens if there is a collision?"
The interviewer wants to hear not just the definition, but the underlying implementation:
- Hash function how to calculate index
- Conflict resolution strategies: chaining vs open addressing (linear probing, secondary probing, double hashing)
- rehashing timing (load factor > threshold)
Answer Suggestion:
"HashTable underlying is array + hash function to locate index. collision commonly used chaining (i.e. each bucket is a chained list or tree), can also use open addressing. load factor exceeds the threshold will be expanded and rehash the whole table. "
This paragraph is delivered in a clear, structured manner and will give the interviewer the impression that you understand the code implementation level thoroughly.
2. Load Balancing (DBMS direction)
Q: "At the database level, how is load balancing implemented?"
Answer Logic Suggestion:
- Application layer load balancing: read/write shunting via proxy (e.g. HAProxy, Nginx)
- Data layer load balancing: master-slave structure + replica allocation
- Dynamic scaling: dynamic node scaling with consistent hashing
The overall logic suggests that we first talk about the goal (equalize the number of requests, reduce bottlenecks) → then talk about the strategy (static vs. dynamic) → and finally give examples of technical solutions.
3. How DNS works
Ask, "Can you explain how DNS works when you visit a website?"
Answer Template:
"When a user enters a URL, the browser first checks the local DNS cache. If not found, it queries the OS, then the resolver (usually the ISP). The resolver performs recursive queries - root → TLD → authoritative name server - until it gets the IP address. Finally, the IP Finally, the IP is cached locally and the browser initiates a TCP connection."
An addendum of "Modern CDNs may use DNS-based load balancing to return geographically nearest IPs" would complete the answer.
post-interview summary
whole duration (of a competition or match) bytedance software engineer interview questions Not too tricky, the interviewer has a gentle tone but requires very clear thinking. They wanted to see:
- Can you keep it structured in coding?
- Do you talk about the project in a way that touches on the technical depth
- Do you really know the underlying principles rather than memorizing them?
This participant received a strong hire overall because of good coding and project performance, although there were some jerks in the eight strands.
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