3822. Design Order Management System

You are asked to design a simple order management system for a trading platform.

Each order is associated with an orderId, an orderType ("buy" or "sell"), and a price.

An order is considered active unless it is canceled.

Implement the OrderManagementSystem class:

• OrderManagementSystem(): Initializes the order management system.
• void addOrder(int orderId, string orderType, int price): Adds a new active order with the given attributes. It is guaranteed that orderId is unique.
• void modifyOrder(int orderId, int newPrice): Modifies the price of an existing order. It is guaranteed that the order exists and is active.
• void cancelOrder(int orderId): Cancels an existing order. It is guaranteed that the order exists and is active.
• vector<int> getOrdersAtPrice(string orderType, int price): Returns the orderIds of all active orders that match the given orderType and price. If no such orders exist, return an empty list.

Note: The order of returned orderIds does not matter.

Example 1:

Constraints:

• 1 <= orderId <= 2000
• orderId is unique across all orders.
• orderType is either "buy" or "sell".
• 1 <= price <= 109
• The total number of calls to addOrder, modifyOrder, cancelOrder, and getOrdersAtPrice does not exceed 2000.
• For modifyOrder and cancelOrder, the specified orderId is guaranteed to exist and be active.