Trees & Graphs

Intermediate

Databases use B-trees, networks are graphs, and every org chart is a tree. Understanding traversal and shortest-path thinking makes you better at designing schemas, APIs, and dependency systems.

3/15

Foundations

Invert Binary TreeRecursive Swap

Easy5m

Maximum Depth of Binary TreeDFS Base Case

Easy5m

Same TreeParallel DFS

Easy5m

Level Order TraversalBFS with deque

Medium12m

Validate BSTIn-order Bounds

Medium12m

Core

Lowest Common AncestorRecursive LCA

Medium12m

Binary Tree Right Side ViewBFS Last Node

Medium12m

Number of IslandsGrid DFS/BFS

Medium15m

Course ScheduleTopological Sort

Medium18m

Word LadderBFS Shortest Path

Hard25m

Intermediate

Clone GraphDFS + HashMap

Medium15m

Pacific Atlantic Water FlowMulti-source DFS

Medium20m

Serialize and Deserialize TreePreorder + Queue

Hard25m

Diameter of Binary TreeDFS Height

Easy10m

Subtree of Another TreeRecursive Match

Easy10m