Trees & Graphs
26 problems · Easy to Hard · Trees, graphs, and traversal
Trees and graphs are the most algorithmically rich topic in technical interviews, spanning traversal, shortest path, topological ordering, and connectivity. This is the largest track in the course — starting with binary tree fundamentals and BST operations, moving through graph traversal with BFS and DFS, and building to advanced topics including Dijkstra's algorithm, Tarjan's bridge-finding algorithm, and Kruskal's minimum spanning tree.
Why it matters:
Graph problems appear in senior-level interviews at every major tech company because they require both pattern recognition and algorithmic depth. The ability to model a real-world problem as a graph and select the right traversal strategy — BFS for shortest paths, DFS for connectivity, topological sort for dependencies — is one of the clearest signals of an experienced algorithmic thinker.