Return All Nodes Reachable from a Starting Vertex
Company: SoFi
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Technical Screen
Given directed edges and a starting vertex, return all vertices reachable from the start, including the start. The graph may contain cycles.
Implement:
```python
def reachable_nodes(edges: list[tuple[str, str]], start: str) -> list[str]:
pass
```
Return vertices sorted lexicographically.
Quick Answer: Practice a SoFi coding interview problem focused on return all nodes reachable from a starting vertex. The prompt emphasizes edge cases, clean implementation, and verifiable test behavior without revealing the solution.
Return all nodes reachable from a start node in a directed graph with cycles.
Examples
Input: {"edges":[["A","B"],["B","C"],["B","D"],["D","E"],["E","B"]],"start":"A"}
Expected Output: ["A","B","C","D","E"]
Explanation: Cycle handled.
Input: {"edges":[],"start":"A"}
Expected Output: ["A"]
Explanation: Start only.