Practice/DoorDash/Round Robin Algorithm: Debugging and Testing

Round Robin Algorithm: Debugging and Testing

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Problem

You're building a load balancer that distributes incoming requests across multiple backend servers. Your task is to implement the round robin algorithm, which cycles through available servers in sequential order.

Given a list of server identifiers and a number of incoming requests, return a list showing which server handles each request in order. The algorithm should:

• Start with the first server in the list
• Move to the next server for each subsequent request
• Wrap back to the first server after reaching the end of the list

Requirements

1. Implement a function that takes a list of server identifiers and a request count
2. Return a list showing the server assignment for each request in order
3. Use the round robin strategy: cycle through servers sequentially
4. Handle edge cases like zero requests or a single server

Constraints

• 1 ≤ servers.length ≤ 100
• 0 ≤ num_requests ≤ 10,000
• Server identifiers are non-empty strings
• Time complexity: O(n) where n is the number of requests
• Space complexity: O(n) for the output list

Examples

Example 1:

Input: servers = ["web-1", "web-2", "web-3"], num_requests = 5 Output: ["web-1", "web-2", "web-3", "web-1", "web-2"] Explanation: The first request goes to web-1, second to web-2, third to web-3, then we wrap around: fourth to web-1, fifth to web-2.

Example 2:

Input: servers = ["api-server"], num_requests = 3 Output: ["api-server", "api-server", "api-server"] Explanation: With only one server, all requests are handled by it.

Example 3:

Input: servers = ["db-1", "db-2"], num_requests = 0 Output: [] Explanation: No requests means an empty result list.