DSA by domain
Web & Backend
Product engineering: the everyday interview core of arrays, strings, two pointers and sliding window.
What the roles here have in common
2 topics are core for every one of the 5 roles in Web & Backend. Whatever job you end up interviewing for inside this domain, this is the part that was never optional:
12 more topics are core for some of these roles but not all of them. Which ones apply is exactly what changes when you pick your role below:
Roles in this domain
Same 370 problems, re-sequenced per role. Pick the exact one you are interviewing for. Every role opens its own roadmap, and the roles with a full guide open the guide.
- SDEThis is the widest DSA bar of any role here: 10 core topics, 260 of our 370 problems. Trees, graphs and dynamic programming carry the loop, and there is no shortcut around them. A generalist SDE interview can pull from almost anywhere. Budget the most time of any track on this list.260 of 370 problems sit in its core topics, starting with Arrays, Strings, Linked List.
- backendBackend rounds keep coming back to the same few problems: an LRU cache, a rate limiter, meeting rooms with a heap, top-K and job queues. Hash maps with linked lists, heaps, sliding windows and intervals carry most of the loop. Hard dynamic programming and backtracking are the exception, not the rule.167 of 370 problems sit in its core topics, starting with Arrays, Strings, Linked List.
- frontendFrontend loops lean on arrays, strings and two-pointer work: 6 core topics, 84 of our 370 problems. Hard dynamic programming is rare. That is a materially smaller surface than a backend loop; grinding a generalist sheet top-to-bottom means spending weeks on segment trees your interview will never mention.84 of 370 problems sit in its core topics, starting with Arrays, Strings, Two Pointers.
- full-stackFull-stack loops blend frontend array/string work with backend structure questions: 7 core topics, 97 problems, and an unusually large second tier (103 problems). Per-topic depth is shallower than a pure backend loop, but the spread is wider: you get asked a little of everything.97 of 370 problems sit in its core topics, starting with Arrays, Strings, Two Pointers.
- SDET / QASDET loops are not the light coding round people expect. Candidate reports from 2024-2025 describe Amazon running 5 DSA questions in 90 minutes and Zomato opening with 3. Arrays and strings dominate: 7 core topics covering 96 of our 370 problems, with 56 of those 96 at medium difficulty. Budget real algorithm time, not a token pass.96 of 370 problems sit in its core topics, starting with Arrays, Strings, Two Pointers.