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Implement Server Number Allocation | Oura Coding Question

Implement Server Number Allocation

Company: Oura

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Take-home Project

Implement a server number allocator for a data center. Servers have a string `type`, such as `"web"`, `"database"`, or `"cache"`. Each server type has its own independent namespace of positive integer server numbers starting from `1`. Design a class that supports the following operations efficiently: - `allocate(type: string) -> int`: Assign and return a server number for the given server type. - Return the smallest currently available positive integer for that type. - If no released number is available, assign the next new number for that type. - `release(type: string, number: int) -> void`: Release a previously allocated server number so it can be reused later for the same server type. Requirements: - Server numbers are independent across types. For example, `web` server `1` and `database` server `1` can both exist at the same time. - A number that is currently allocated must not be allocated again for the same type. - Released numbers should be reused before creating larger numbers, using the smallest available released number first. - Handle a large number of allocation and release requests efficiently. Example: ```text allocate("web") -> 1 allocate("web") -> 2 allocate("database") -> 1 release("web", 1) allocate("web") -> 1 allocate("web") -> 3 ```

Quick Answer: This question evaluates the ability to design efficient stateful data structures and algorithms for resource allocation, focusing on management of per-type namespaces and correct reuse of released identifiers.

Simulate allocate and release operations for independent server-type namespaces, returning allocated numbers.

Constraints

Inputs are Python literals matching the function signature.
Return a deterministic exact-match value.

Examples

Input: ([["allocate","web"],["allocate","web"],["allocate","database"],["release","web",1],["allocate","web"]],)

Expected Output: [1, 2, 1, 1]

Explanation: Namespaces are independent and released web 1 is reused.

Input: ([["release","web",1],["allocate","web"],["release","web",1],["release","web",1],["allocate","web"]],)

Expected Output: [1, 1]

Explanation: Invalid or duplicate releases are ignored.

Input: ([["allocate","cache"],["allocate","cache"],["release","cache",2],["release","cache",1],["allocate","cache"],["allocate","cache"]],)

Expected Output: [1, 2, 1, 2]

Explanation: The smallest released number is reused first.

Hints

Keep a min-heap of released numbers per type.
Also track allocated numbers to ignore invalid releases.

Quick Overview

This question evaluates the ability to design efficient stateful data structures and algorithms for resource allocation, focusing on management of per-type namespaces and correct reuse of released identifiers.