Graph Traversal Basics

1. Which traversal guarantees shortest path in an unweighted graph?

BFS DFS Dijkstra Topological sort

2. Grid problems usually use which neighbor directions?

3. When should you mark a node visited to avoid duplicates?

When enqueuing/pushing When dequeuing/popping After exploring all nodes Never

4. If newColor equals the starting color in flood fill, the best action is:

Return immediately Run DFS anyway Invert all colors Throw error

5. What data structure supports BFS order?