Data Structures & Algorithms

The backbone of coding interviews — know your data structures and when to use each.

Topic	Key Focus
Arrays & Strings	Manipulation, Sliding window, Two pointers
Linked Lists	Singly, Doubly, Cycle detection, Reversal
Stacks & Queues	Monotonic stack, BFS, Priority queues
Hash Maps	Hashing, Collisions, Load factor, Rehashing
Trees	BST, AVL, Traversals, LCA
Graphs	BFS, DFS, Shortest path, Topological sort
Heaps	Min/Max heap, Heap sort, Top-K problems
Tries	Prefix trees, Autocomplete, Word search
Sorting	Quick, Merge, Heap, Counting, Radix
Searching	Binary search, Search in rotated array
Dynamic Programming	Memoization, Tabulation, Common patterns
Greedy	Activity selection, Huffman, Interval scheduling
Backtracking	N-Queens, Sudoku, Permutations, Subsets
Sliding Window & Two Pointer	Variable/Fixed window, Fast/Slow pointers