| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 201 | Red-Black Tree | Hard | Advanced DSSelf-Balancing Tree |
| 202 | B-Tree Implementation | Hard | Advanced DSMulti-way Tree |
| 203 | Segment Tree with Lazy Propagation | Hard | Advanced DSSegment TreeRange Query |
| 204 | Fenwick Tree (BIT) | Hard | Advanced DSBinary Indexed Tree |
| 205 | Disjoint Set Union (Union-Find) | Hard | Advanced DSUnion-FindPath Compression |
| 206 | Suffix Array Builder | Hard | Advanced DSStringArray |
| 207 | Treap (Tree + Heap) | Hard | Advanced DSBSTHeap |
| 208 | Persistent Data Structure | Hard | Advanced DSImmutableVersioning |
| 209 | Leftist Heap | Hard | Advanced DSHeapMerge |
| 210 | Van Emde Boas Tree | Hard | Advanced DSTreeBit Operations |
| 211 | Splay Tree | Hard | Advanced DSBSTSelf-Adjusting |
| 212 | Interval Tree | Hard | Advanced DSBSTIntervals |
| 213 | K-D Tree | Hard | Advanced DSTreeMulti-dimensional |
| 214 | Cartesian Tree Builder | Hard | Advanced DSTreeStack |
| 215 | Rope Data Structure | Hard | Advanced DSTreeString |
| 216 | Bellman-Ford Algorithm | Hard | Advanced GraphsGraphShortest Path |
| 217 | Floyd-Warshall All Pairs | Hard | Advanced GraphsGraphDP |
| 218 | Tarjan's Strongly Connected Components | Hard | Advanced GraphsGraphDFS |
| 219 | Articulation Points and Bridges | Hard | Advanced GraphsGraphDFS |
| 220 | Maximum Flow (Ford-Fulkerson) | Hard | Advanced GraphsGraphFlow Network |