Practice/Amazon/Design a Product Stock Availability Service

Design a Product Stock Availability Service

Object Oriented DesignMust

Problem

You are building an inventory management system for a large e-commerce platform that operates multiple distribution centers across different regions. Each warehouse maintains its own independent database tracking product inventory levels. When a customer attempts to purchase a product, the system needs to quickly determine whether sufficient stock exists across all warehouses to fulfill the order.

Design and implement a function that checks whether a specific product has enough total inventory across all warehouses to satisfy a customer's order quantity. The function should aggregate stock levels from multiple warehouse databases and return whether the order can be fulfilled.

Requirements

1. Implement a function that accepts a product identifier, required quantity, and a list of warehouse inventory data
2. Each warehouse has an independent inventory system represented as a dictionary mapping product IDs to available quantities
3. Calculate the total available inventory across all warehouses for the requested product
4. Return true if the combined inventory meets or exceeds the required quantity, false otherwise
5. Handle cases where the product may not exist in some or all warehouses
6. The solution should be efficient enough to handle queries across dozens of warehouses

Constraints

• 1 ≤ number of warehouses ≤ 100
• Product IDs are non-empty strings
• 1 ≤ quantity_needed ≤ 10,000
• 0 ≤ stock quantity per warehouse ≤ 10,000
• Each warehouse may have 0 to 1,000 different products in inventory
• Time complexity should be O(n) where n is the number of warehouses
• Space complexity should be O(1) excluding the input

Examples

Example 1:

Input: product_id = "LAPTOP-X1" quantity_needed = 3 warehouses = [ \{"id": "NYC", "stock": \{"LAPTOP-X1": 2, "PHONE-A": 10\}\}, \{"id": "LA", "stock": \{"LAPTOP-X1": 5, "TABLET-B": 7\}\} ] Output: true Explanation: NYC has 2 units and LA has 5 units of LAPTOP-X1, totaling 7 units which exceeds the required 3 units.

Example 2:

Input: product_id = "MONITOR-Z" quantity_needed = 10 warehouses = [ \{"id": "CHICAGO", "stock": \{"MONITOR-Z": 3\}\}, \{"id": "DALLAS", "stock": \{"MONITOR-Z": 4\}\}, \{"id": "MIAMI", "stock": \{"KEYBOARD-K": 20\}\} ] Output: false Explanation: Only 7 units are available (3 + 4 + 0), which is less than the required 10 units.

Example 3:

Input: product_id = "HEADSET-H" quantity_needed = 1 warehouses = [ \{"id": "SEATTLE", "stock": \{"MOUSE-M": 15\}\}, \{"id": "BOSTON", "stock": \{"CABLE-C": 30\}\} ] Output: false Explanation: The product HEADSET-H is not available in any warehouse.