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// Phase 2 · Coding interviews · course 3

Data Structures & Algorithms

Every pattern behind coding interviews: Big-O, hash maps, two pointers, windows, intervals, trees, tries, graphs, greedy and DP.

Intermediate⭐ Advanced · members23 lessons ready5 coming soon

You'll be able to

  • Analyze time and space complexity with Big-O
  • Recognize the right pattern: hash map, two pointers, monotonic stack, sliding window, prefix sums, intervals, greedy, BFS/DFS, trie, heap or DP
  • Implement linked lists, trees and graph searches from scratch
  • Design O(1) data structures like an LRU cache
  • Run a 45-minute coding interview with a clear, confident script

Syllabus

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  1. 1Big-O in Plain EnglishHow to describe the speed of your code, and why interviewers always ask.🔒12 min
  2. 2Hash Maps & SetsThe single most useful pattern for turning slow solutions into fast ones.🔒14 min
  3. 3Two Pointers & StacksTwo more patterns that unlock a large share of easy and medium interview questions.🔒15 min
  4. 4The Monotonic StackFind the "next greater" or "next smaller" element for every item in one pass.🔒14 min
  5. 5The Sliding Window PatternSolve "best stretch of the array" problems in one pass instead of two loops.🔒12 min
  6. 6Prefix SumsPrecompute running totals once, then answer any "sum of a range" question instantly.🔒13 min
  7. 7Binary SearchFind anything in a sorted list of a billion items in about 30 steps.🔒12 min
  8. 8Sorting Algorithms, VisualizedWatch bubble, selection and insertion sort run, then learn why real code uses O(n log n).🔒14 min
  9. 9IntervalsSort by start time, then merge, insert or count overlapping ranges in one sweep.🔒14 min
  10. 10Greedy AlgorithmsMake the best local choice at every step, and learn how to tell when that's actually safe.🔒14 min
  11. 11Bit ManipulationRead numbers as rows of 0s and 1s, and use AND, OR, XOR and shifts for fast tricks.🔒13 min
  12. 12Recursion, Step by StepFunctions that call themselves. Watch the call stack grow and shrink.🔒14 min
  13. 13Linked ListsNodes that point to the next node. A favorite for learning pointers and an interview classic.🔒12 min
  14. 14Designing Data StructuresCombine hash maps, lists and stacks to build classes like an LRU cache with O(1) operations.🔒16 min
  15. 15Trees & Binary Search TreesHierarchies of nodes, depth-first traversal, and searching in O(log n).🔒15 min
  16. 16Tree TraversalsPre-order, in-order, post-order and level-order, and which one each problem needs.🔒15 min
  17. 17Binary Search Trees in DepthInsert, search, validate and find the k-th smallest, and why balance decides the speed.🔒15 min
  18. 18Tries (Prefix Trees)Store words letter by letter so autocomplete and "starts with" lookups are instant.🔒14 min
  19. 19Heaps & Priority QueuesAlways grab the smallest (or biggest) item fast. Perfect for "top K" problems.🔒10 min
  20. 20Graphs: BFS & DFSModel networks of connections and find paths through them.🔒15 min
  21. 21Grids & Matrix TraversalTreat a 2D grid as a graph, walk it in four directions, and flood-fill islands with BFS or DFS.🔒15 min
  22. 22Dynamic Programming, DemystifiedStop recomputing the same answers. Memoization and tables, explained gently.🔒15 min
  23. 23The 45-Minute Interview, Start to FinishA repeatable script for any coding interview, practiced on a real question.🔒15 min
  24. 24Backtracking: trying every optionComing soon
  25. 25Topological sortComing soon
  26. 26Union-findComing soon
  27. 27Shortest paths (Dijkstra)Coming soon
  28. 28DP on grids and stringsComing soon