DSA Tracker

DSA Interview Roadmap

SDE / Backend Engineer

A SDE / Backend Engineer interview leans on 306 of the 370 curated problems. The other 64 are lower frequency for this role — still here, just not first.

The broadest DSA bar — trees, graphs, and DP show up most; this is the classic generalist interview loop.

Focus on
306
Core topics
10
Deprioritise
64
Full catalogue
370

Track your progress on this roadmap — the map fills itself as you solve.

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What this interview looks like

Backend loops test how candidates isolate state mutations under concurrency and design maintainable persistence flows. Interviewers probe service reliability by setting up hierarchical dependency trees, recursive traversal scenarios, and stateful transaction chains. Success requires tracking side effects cleanly, proving edge bounds, and explaining structural invariants without stumbling over pointer mutations or recursion depth limits.

What it leans away from

Specialized bit tricks and geometric coordinate calculations sit in the bottom tier because distributed services spend runtime marshalling RPC payloads rather than shifting raw bytes. While bit operations and numeric interval packing rarely surface on main interview loops, teams building network protocols or custom serialization engines occasionally introduce them during specialized rounds.

The whole path

CoreRole-specificAdvanced
  1. Phase 1 - DSA Foundation
    Arrays34Strings22Linked List17Binary Trees32BST20Graph48Dynamic Programming51Stack16Queue4Binary Search16
  2. Phase 2 - Role Skill Gaps
    Backtracking12Heap13Two Pointers6Sliding Window8Recursion7
  3. Phase 3 - Projects and Interview Proof
    Math11Bit Manipulation11Trie9Intervals5Matrix6Sorting7Greedy15
1

Phase 1 - DSA Foundation

The curation places 10 core topics first for this role, leading with practice problems.

  1. 01ArraysCore
    34 problemsVisualize
    Two SumMaximum and Minimum Element in an ArrayReverse the ArrayContains DuplicateRead the theory
  2. 02StringsCore
    22 problemsVisualize
    Valid PalindromeValid AnagramImplement strStr()Longest Common PrefixRead the theory
  3. 03Linked ListCore
    17 problemsVisualize
    Reverse Linked ListLinked List CycleMerge Two Sorted ListsMiddle of Linked ListRead the theory
  4. 04Binary TreesCore
    32 problemsVisualize
    Binary Tree Inorder TraversalBinary Tree Preorder TraversalBinary Tree Postorder TraversalMaximum Depth of Binary TreeRead the theory
  5. 05BSTCore
    20 problemsVisualize
    Two Sum in BSTValidate Binary Search TreeLowest Common Ancestor of a BSTKth Smallest Element in a BSTRead the theory
  6. 06GraphCore
    48 problemsVisualize
    Flood FillNumber of IslandsClone GraphCourse ScheduleRead the theory
  7. 07Dynamic ProgrammingCore
    51 problemsVisualize
    Climbing StairsN-th Tribonacci NumberCoin ChangeLongest Increasing SubsequenceRead the theory
  8. 08StackCore
    16 problemsVisualize
    Valid ParenthesesNext Greater Element IMin StackEvaluate Reverse Polish NotationRead the theory
  9. 09QueueCore
    4 problemsVisualize
    Implement Queue using StacksImplement Stack using QueuesFirst Non-Repeating Character in StreamSliding Window MaximumRead the theory
  10. 10Binary SearchCore
    16 problemsVisualize
    Binary SearchSearch Insert PositionSqrt(x)Lower Bound and Upper BoundRead the theory
2

Phase 2 - Role Skill Gaps

The curation balances theory and practice equally across these role-specific topics to complete the 306 focus problems.

  1. 11BacktrackingRole-specific
    12 problemsVisualize
    Read the theorySubsetsSubsets IICombination SumCombination Sum II
  2. 12HeapRole-specific
    13 problemsVisualize
    Read the theoryKth Largest Element in a StreamLast Stone WeightK Closest Points to OriginTask Scheduler
  3. 13Two PointersRole-specific
    6 problemsVisualize
    Read the theoryValid Palindrome IIMove ZeroesRemove Duplicates from Sorted ArraySquares of a Sorted Array
  4. 14Sliding WindowRole-specific
    8 problemsVisualize
    Read the theoryMinimum Size Subarray SumFruit Into BasketsNumber of Substrings Containing All Three CharactersMax Consecutive Ones III
  5. 15RecursionRole-specific
    7 problemsVisualize
    Read the theoryFactorialFibonacci NumberFlood Fill (Recursion)Tower of Hanoi
3

Phase 3 - Projects and Interview Proof

The curation pushes 64 problems down for this role, so understanding the theory is the goal here.

  1. 16MathAdvanced
    11 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems
  2. 17Bit ManipulationAdvanced
    11 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems
  3. 18TrieAdvanced
    9 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems
  4. 19IntervalsAdvanced
    5 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems
  5. 20MatrixAdvanced
    6 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems
  6. 21SortingAdvanced
    7 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems
  7. 22GreedyAdvanced
    15 problemsVisualize
    Read the primerunderstanding is the goal here rather than grinding problems

Ready to actually walk this path?

Every topic above links to real problems, step-by-step pattern visualizers, and an in-browser compiler. Your progress tracks automatically as you solve.

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SDE / Backend Engineer DSA questions, answered

How many DSA problems does a SDE / Backend Engineer need to solve?

About 306 of the 370 curated problems. Those sit in the 10 topics a SDE / Backend Engineer interview leans on; the remaining 64 are lower frequency for this role and are worth doing later rather than first.

Which DSA topics matter most for a SDE / Backend Engineer?

Arrays, Strings, Linked List, Binary Trees, BST, Graph and others — the core tier for this role. Topic priority is mapped per role rather than shared, so a SDE / Backend Engineer path deliberately differs from a generic sheet order.

Can a SDE / Backend Engineer skip some DSA topics?

Deprioritise rather than skip. 64 of the 370 problems are lower frequency for a SDE / Backend Engineer, so they belong after the core tier — not never, but not first. Interviews do occasionally reach outside the common ground.

Is this SDE / Backend Engineer roadmap free?

Yes. The roadmap, the problem list, the pattern walkthroughs and progress tracking are all free with no signup required to read. Only AI-generated insights are metered.

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Problem set and role mapping as of .