Data structures

Core data structures with SDE-3 level content: concept overview, algorithms, patterns, code, interview strategy, and quick revision.

Topic files

Topic	File	Highlights
Array	array.md	Two pointers, sliding window, prefix sum, Kadane; edge cases, SDE-3 trade-offs.
Linked List	linked-list.md	Dummy node, fast/slow, in-place reversal, cycle detection; LRU (design).
Stack	stack.md	Monotonic stack, next greater element, largest rectangle in histogram.
Queue	queue.md	BFS, monotonic deque, sliding window maximum, circular queue.
Tree	tree.md	Traversals, LCA, tree DP, BST, max path sum, serialize/deserialize.
Heap	heap.md	Top-K, K-way merge, two heaps (median), implementations.
Hashing	hashing.md	Collision handling, subarray sum = K, consistent hashing, bloom filter.
Graphs	graphs.md	BFS/DFS, islands, flood fill, rotten oranges, course schedule, alien dictionary; terminology, algorithms, question lists.

How to use

• Learn a topic: Open the topic file; read Concept Overview → Core Algorithms → Pattern Recognition → Interview Strategy → Quick Revision.

• Before interviews: Use each file’s Quick Revision and Interview Strategy sections.

• Patterns: See also patterns/two-pointers-sliding-window.md and patterns/leetcode-patterns.md.

Cross-links

• Graph algorithms (Dijkstra, topo, MST): ../algorithms/graph.md

• Union Find (connectivity, Kruskal): ../algorithms/union-find.md