ByteDance Interview Guide

ByteDance runs the most competitive-programming-flavoured loop of the companies here. The algorithmic bar is high and the problems skew harder than the big-five median — expect genuine hard problems, tighter time limits, and follow-ups that go deeper into complexity rather than sideways into systems.

The loop also varies by region more than most: the process, the number of rounds and the emphasis differ between the China, Singapore and US pipelines. Ask your recruiter which one you are in.

Crowd-reported, not published

No company publishes its question bank. The round structure and the bar below are corroborated by recruiters and candidates; the problem list is crowd-reported, stale, and biased toward whoever posted it. Treat the pattern families as the durable signal — which families a company leans on changes far more slowly than which individual problems it uses.

The hardest pure-algorithm bar of the group, and the closest to competitive programming. Hard-tier DP, string algorithms and advanced data structures appear at frequencies the other companies do not approach.

The loop

Online assessment 1× · 90-120 min 3-4 problems, contest-style difficulty

Technical 3-4× · 60 min Two problems per round, mediums and hards

HR / cross 1× · 30-45 min Fit and motivation

The bar

Treat preparation as competitive programming rather than interview prep. Segment trees, string hashing and non-obvious DP states are in scope.

What they lean on

This is the durable part. Which pattern families a company favours is far more stable than which individual problems it uses, so prepare in this order:

1. segment-trees-and-lazy-propagation
2. advanced-dp-optimizations
3. string-algorithms-kmp-z-and-rabin-karp
4. bitmask-and-tree-dp
5. binary-search-on-answer
6. monotonic-deque
7. number-theory-for-competitive-programming

Quirks worth knowing

• The online assessment is genuinely contest-difficulty and is the main filter. Practise under time pressure.
• Phases 16 and 17 of this course are not optional here, unlike at the other companies.
• Multiple rounds may run on the same day with little gap. Stamina matters.

Reported problems

Read this before you trust the list. No company publishes its question bank. Every "asked at ByteDance / TikTok" list in circulation — including this one — is aggregated from candidate reports, is months to years out of date, and over-represents whoever bothered to post. Use it to choose an order to practise in. Do not use it as a question bank, and do not assume a problem missing from it is safe to skip.

15 problems

0 easy10 medium5 hard

AllEasyMediumHard

Unsolved onlyExportImportReset

• ○200Number of IslandsmediumNeetCode 150Blind 75LeetCode Top Interview 150
• ○72Edit DistancemediumNeetCode 150LeetCode Top Interview 150
• ○102Binary Tree Level Order TraversalmediumNeetCode 150Blind 75LeetCode Top Interview 150
• ○139Word BreakmediumNeetCode 150Blind 75LeetCode Top Interview 150
• ○207Course SchedulemediumNeetCode 150Blind 75LeetCode Top Interview 150
• ○300Longest Increasing SubsequencemediumNeetCode 150Blind 75LeetCode Top Interview 150
• ○322Coin ChangemediumNeetCode 150Blind 75LeetCode Top Interview 150
• ○347Top K Frequent ElementsmediumNeetCode 150Blind 75
• ○875Koko Eating BananasmediumNeetCode 150
• ○994Rotting OrangesmediumNeetCode 150
• ○4Median of Two Sorted ArrayshardNeetCode 150LeetCode Top Interview 150
• ○84Largest Rectangle in HistogramhardNeetCode 150
• ○127Word LadderhardNeetCode 150LeetCode Top Interview 150
• ○212Word Search IIhardNeetCode 150Blind 75LeetCode Top Interview 150
• ○239Sliding Window MaximumhardNeetCode 150

Pitfalls

• Preparing for medium difficulty. The distribution genuinely skews harder here. If your hard-problem count is low, that is the gap.
• Being imprecise about complexity. Follow-ups drill into the bound rather than into system design. Know the difference between amortised and worst case, and which variable your bound is over.
• Assuming a standard loop. Round counts and emphasis differ substantially by region. Ask.
• Neglecting implementation speed. With harder problems in the same time box, fluency with heapq, bisect, itertools and the DP templates matters more than at companies with an easier distribution.

Interview follow-ups

They ask	What they’re checking	The answer
“Can you do better than $O(n^2)$?”	Algorithmic depth	Name the specific bottleneck rather than saying yes. If the sort dominates, say so; if the transition is the problem, name the structure that removes it — a monotonic deque, a segment tree, a prefix-sum trick.
“Prove that bound.”	Precision under pressure	For an amortised bound, give the potential argument: each element is pushed once and popped once, so total inner-loop work is bounded by n. Nesting is not the bound.
“What is the complexity in terms of the constraint, not $n$?”	Whether you name the right variable	Binary search on the answer is $O(n \log R)$ in the value range; knapsack is $O(nW)$ in the capacity. Quoting either as a function of n alone is the slip they are probing.
“Which region’s loop are you in?” (you asking)	Basic diligence	Ask the recruiter. The pipelines differ enough that it changes what to expect.

Recall card

• Hardest algorithmic distribution here. If your hard-problem count is low, that is the gap.
• Complexity follow-ups go deeper, not sideways. Amortised versus worst case, and which variable the bound is over.
• Be able to prove an amortised bound — pushed once, popped once, total work bounded by n.
• Implementation fluency matters more — harder problems in the same time box.
• The loop varies by region. Ask which pipeline you are in.