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Course 3⭐ Members

Data Structures & Algorithms

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

Lessons

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