ByteDance interview notes, page 18 of 29

FAANG / Big Tech

Most of these ByteDance write-ups come from Software Engineers (194), then Machine Learning Engineers (45) and Data Scientists (17). The most reported rounds are the technical phone screen (227), the system design round (28), the behavioral / leadership round (16) and the onsite coding round (9).

289 interview notes · updated Sep 2026

ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance SRE interview with a graph reachability problem that looked deceptively simple. The complexity analysis at the end is what they actually care about.

You have n devices, each with a position (x, y) and a range r. Device i can activate device j if the Euclidean distance between them is at most r_i, but not necessarily the other way around. If you manually activate one device, all devices reachable from it directly or through a chain also activate. Which starting device maximizes the total number of activated devices? Also walk through the time and space complexity of your solution.

“This is a directed graph problem disguised as a geometry question.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance SWE interview that went deep on browser internals and networking. One long question that just kept going, layer after layer.

Walk through everything that happens technically when a mobile phone opens a web page, from typing the URL to pixels on screen. Cover DNS, TCP/TLS, HTTP request and response, server processing, HTML/CSS/JS parsing, render tree, layout, painting, and mobile-specific factors like cellular latency and caching.

“This question started feeling manageable and then just didn't stop.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance SET interview that leaned harder on algorithms than I expected. The palindrome substring problem sounds like a warmup but they pushed me through multiple solution tiers, so come prepared to actually discuss tradeoffs not just code one approach.

Given a string, find the longest palindromic substring and walk through multiple approaches including a quadratic solution, dynamic programming, and a linear time algorithm.

“Started with expand-around-center which felt safe, but then they asked me to keep going.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance SWE interview with a classic algorithmic problem. Nothing too wild but the O(n^2) constraint made it clear they wanted a specific approach, not just any working solution.

Given an integer array, find all unique triplets that sum to zero. No duplicate triplets in the result, and you need to do it in O(n^2) time.

“My first instinct was a brute force triple loop which obviously wasn't going to fly.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance SWE interview with an algorithmic problem that starts simple and then asks you to do better. The follow-up is where things get interesting and probably where most people stumble.

Given a sorted integer array of length n (n >= 3), find all distinct values that appear strictly more than n/3 times. Return them in increasing order. Then, once you have the linear solution, optimize it to run faster than O(n) using the sorted property.

“The base version is fine, just count runs since the array is sorted.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance SRE interview with a graph traversal problem that looks straightforward until you miss the asymmetry detail and your whole approach falls apart.

You have n bombs, each with a position and explosion radius. Detonating one bomb triggers any other bomb whose center falls within that radius, and those bombs trigger their own, chain-reaction style. Find the starting bomb that causes the maximum total detonations.

“My first instinct was to just check all pairs and do some kind of flood fill, which is basically right, but I initially modeled it as an undirected graph and that was wrong.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Bytedance software engineer round that was basically one big two-part coding problem: validate an arithmetic expression, then evaluate it. The kind of question that feels manageable until you start edge-casing it to death.

Given an input string, determine whether it is a syntactically valid arithmetic expression. The string may contain digits, the operators +, -, *, /, spaces, and parentheses. You need to handle things like balanced parentheses, no adjacent operators, and no leading or trailing operators.
Now evaluate the valid arithmetic expression and return the result. Operator precedence applies: multiplication and division before addition and subtraction, with parentheses overriding that order. Handle negative numbers.

“I thought I had this.”

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ByteDance·Software Engineer·Technical Phone Screen

Jun 2026

Late in a Bytedance SRE interview, they threw a coding question at me when my brain had basically already checked out. A variant of a LeetCode problem, not the hardest thing in the world, but after everything else that round it felt like running the last mile on fumes.

Solve a coding problem that is a variant of LeetCode 456.

“By the time this came up I was completely fried.”

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ByteDance·Software Engineer·Onsite - System Design / Architecture

Jun 2026

Bytedance system design round, one question but it had a lot of moving parts. They wanted a full LRU cache design with TTL baked in, which sounds manageable until you get to the cleanup and concurrency bits.

Design an in-memory LRU cache that supports TTL expiration. Cover the data structures, eviction logic, how expired entries get cleaned up, time complexity, and concurrency.

“I went with the classic hashmap plus doubly linked list combo and felt pretty good about the get and put logic.”

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ByteDance·Backend Engineer·Technical Phone Screen

Jun 2026

Bytedance backend screen, just one database fundamentals question from what I can tell. Pretty standard stuff but worth writing down.

Can you explain what primary keys, foreign keys, and indexes are in a relational database?

“Covered the basics fine.”

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