Arrays and hashing
Frequency maps, prefix sums, intervals, and lookup-based problems.
Visual interview preparation
128 important DSA interview problems
Watch arrays, linked lists, trees, graphs, sorting, and matrix problems unfold step by step in short video walkthroughs with C++ code. Learn the pattern and reasoning instead of memorizing a final answer.
Practice by pattern
Build reusable problem-solving skill
Two pointers and windows
Sorted pairs, partitions, contiguous ranges, and frequency windows.
Stacks, queues, and heaps
Monotonic structures, scheduling, top-k questions, and stream processing.
Trees and graphs
Traversal, shortest paths, connectivity, ordering, and recursive structure.
Backtracking and dynamic programming
Search choices, overlapping states, optimization, and reconstruction.
Interview simulations
Constraints, baseline solutions, edge cases, complexity, and clean implementation.