Traverse an HTTP Maze with Retry Handling

Problem Statement

You are given a web crawler interface that allows you to explore an HTTP-based maze. The goal is to find the shortest number of requests required to reach an "EXIT" URL from a "START" URL.

Your task is to implement the function findShortestPath(startUrl, httpClient).

The API

• httpClient.get(url) returns a response object:
  • status: Integer status code.
  • links: A list of strings (neighbor URLs).
  • isExit: Boolean indicating if the URL is the exit.
• Error Handling:
  • Status 200: Success. You receive the links.
  • Status 4xx: Client error. These are permanent; do not retry.
  • Status 5xx: Server error. You must retry up to 3 times for a specific URL before giving up on that path.

Constraints

• Use Breadth-First Search (BFS) to find the shortest path.
• Maintain a set of visited URLs to avoid cycles.
• The function should return the minimum number of HTTP requests made to find the exit, or -1 if unreachable.

Example

# Interface
class HttpClient:
    def get(self, url: str) -> Response: pass

def findShortestPath(startUrl: str, httpClient: HttpClient) -> int:
    # Implementation here

Edge Cases

• The maze contains cycles.
• A URL returns a 500 error repeatedly, exceeding the 3-retry limit.
• The startUrl is the exit.