| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 141 | Tree Pretty Printer | Medium | TreesBinary TreeFormatting |
| 142 | Binary Tree Mirror | Medium | TreesBinary TreeRecursion |
| 143 | Count Leaf Nodes | Medium | TreesBinary TreeTraversal |
| 144 | AVL Tree Implementation | Medium | TreesAVL TreeRotation |
| 145 | Symbol Table Implementation | Medium | TreesBSTScoping |
| 146 | Heap Implementation | Medium | TreesHeapArray |
| 147 | Priority Queue | Medium | TreesHeapComparator |
| 148 | Expression Tree Evaluator | Medium | TreesBinary TreeParsing |
| 149 | Adjacency List Graph | Medium | GraphsGraphHashMap |
| 150 | BFS Traversal | Medium | GraphsGraphQueue |
| 151 | DFS Traversal | Medium | GraphsGraphStack/Recursion |
| 152 | Cycle Detection in Graph | Medium | GraphsGraphDFS |
| 153 | Shortest Path (Dijkstra) | Medium | GraphsGraphPriority Queue |
| 154 | Task Dependency Resolver | Medium | GraphsGraphDFS |
| 155 | Connected Components | Medium | GraphsGraphBFS/DFS |
| 156 | Social Network Analyzer | Medium | GraphsGraphBFS |
| 157 | Minimum Spanning Tree | Medium | GraphsGraphGreedy |
| 158 | Graph Path Finder | Medium | GraphsGraphBacktracking |
| 159 | Tower of Hanoi | Medium | RecursionRecursionLogic |
| 160 | Combination Generator with Constraints | Medium | RecursionRecursionConstraints |