Trees
- Binary trees: traversals (inorder, preorder, postorder, level-order), height, depth
- Binary search trees (BST): search, insert, delete, successor/predecessor
- Balanced BSTs: AVL trees (rotations), red-black trees (colour invariants)
- B-trees and B+ trees: disk-friendly, database indexing, order and fill factor
- Tries: prefix trees, autocomplete, word search
- Segment trees: range queries, lazy propagation
- Fenwick trees (Binary Indexed Trees): prefix sums, point updates
- Union-Find (Disjoint Set Union): path compression, union by rank