D
Data Structures & Algorithms
Topic-by-topic DSA: concepts first, then the interview problems that use them.
25 segments · 1417 stations · 674hSegments on this line
- D1 · Arrays271 stations · 111h · Traversal, in-place tricks, Kadane, and the patterns every other topic builds on.
- D2 · Strings104 stations · 38h · String manipulation, KMP, Z-algorithm, Rabin-Karp and palindromes.
- D3 · Hashing48 stations · 19h · Hash maps and sets for counting, lookup and dedup.
- D4 · Prefix Sum & Difference Array20 stations · 8.6h · Prefix sums, difference arrays and line sweep for range updates and queries.
- D5 · Two Pointers15 stations · 5.2h · Opposite-end and fast/slow pointer patterns.
- D6 · Sliding Window52 stations · 28h · Fixed and variable windows over arrays and strings.
- D7 · Binary Search50 stations · 28h · Search on sorted data and binary search on the answer.
- D8 · Sorting11 stations · 4.3h · Comparison sorts, custom comparators, counting sort.
- D9 · Linked List30 stations · 12h · Pointer manipulation, reversal, cycles and merging.
- D10 · Stack37 stations · 17h · Monotonic stacks, expression parsing and next-greater problems.
- D11 · Queue2 stations · 51m · Queues, deques and monotonic deques.
- D12 · Recursion31 stations · 16h · Thinking recursively: the foundation for trees, backtracking and DP.
- D13 · Backtracking25 stations · 12h · Subsets, permutations, combinations and constraint search.
- D14 · Trees64 stations · 23h · Binary tree traversals, views, LCA and path problems.
- D15 · Binary Search Trees5 stations · 1.5h · BST properties, validation, insertion and deletion.
- D16 · Heap / Priority Queue35 stations · 18h · Top-K, scheduling and k-way merge patterns.
- D17 · Graphs145 stations · 75h · BFS, DFS, topological sort, shortest paths and MST.
- D18 · Dynamic Programming210 stations · 125h · From recursion + memo to bottom-up, across all DP patterns.
- D19 · Tries10 stations · 7.1h · Prefix trees for word search and XOR problems.
- D20 · Greedy76 stations · 37h · Exchange arguments, intervals and greedy choice.
- D21 · Bit Manipulation48 stations · 21h · Bitwise tricks, masks and XOR properties.
- D22 · Math76 stations · 36h · Number theory, primes, GCD and combinatorics.
- D23 · Segment Tree & BIT21 stations · 15h · Range queries with updates: segment trees and Fenwick trees.
- D24 · Design Data Structures26 stations · 12h · LRU/LFU caches, randomized sets and other design-a-structure interview classics.
- D25 · Advanced Techniques5 stations · 3.6h · Meet in the middle and other techniques for when brute force is just too slow.