I think I can simplify a lot the implementation
The Scenario
Sellers list their items (iron) with a specific quantity and price per unit.
Buyers place an order for a desired quantity and specify the maximum price they’re willing to pay per unit.
The system matches the buyer with sellers based on the lowest available prices first, ensuring the buyer pays no more than their maximum price and sellers receive exactly what they ask for.
Example, Explained
Sellers’ Offers:
Seller 1 offers 5,000 iron at 4 gold per unit.
Seller 2 offers 5,000 iron at 5 gold per unit.
Total available: 10,000 iron.
Buyer’s Order:
The buyer wants 10,000 iron and is willing to pay up to 6 gold per unit.
This means the buyer’s maximum budget is 10,000 × 6 = 60,000 gold.
How the System Matches:
The system prioritizes the lowest-priced offers first to benefit the buyer.
Seller 1’s offer (4 gold/unit for 5,000 iron) is cheaper, so the buyer purchases all 5,000 iron from Seller 1 at 4 gold/unit.
Cost: 5,000 × 4 = 20,000 gold.
Seller 1 receives exactly 20,000 gold (their asking price).
The buyer still needs 5,000 more iron. Seller 2’s offer (5 gold/unit for 5,000 iron) is next, and since 5 gold is below the buyer’s maximum of 6 gold, the buyer purchases all 5,000 iron from Seller 2 at 5 gold/unit.
Cost: 5,000 × 5 = 25,000 gold.
Seller 2 receives exactly 25,000 gold (their asking price).
Outcome:
The buyer gets the desired 10,000 iron.
Total cost: 20,000 (Seller 1) + 25,000 (Seller 2) = 45,000 gold.
The buyer’s budget was 60,000 gold, but they only spent 45,000 gold, saving 15,000 gold.
Sellers receive exactly their asking prices: Seller 1 gets 20,000 gold, Seller 2 gets 25,000 gold.
Why This Implementation Is Simple
Clear Matching Rule: The system always matches the buyer with the lowest-priced sellers first, as long as the seller’s price is at or below the buyer’s maximum price. This ensures fairness and efficiency.
No Overpayment: The buyer pays exactly what each seller asks for (no more, no less), and only if it fits within their maximum price.
Budget Efficiency: The buyer doesn’t spend their entire budget if cheaper options are available, maximizing their savings.
No Complex Negotiations: Sellers set their price, the buyer sets their maximum, and the system handles the rest automatically.
Potential Edge Cases (to Clarify Further)
What if there’s not enough iron?
If the total available iron is less than 10,000 (e.g., only 8,000 available), the buyer would purchase all 8,000 at the lowest prices (e.g., 5,000 at 4 gold, 3,000 at 5 gold) and stop there. The system doesn’t force the buyer to overpay or buy unwanted items.
What if prices are higher?
If a seller offers iron at 7 gold/unit (above the buyer’s maximum of 6 gold), their offer is ignored. The buyer only considers offers at or below their maximum price.
What if sellers have the same price?
If two sellers offer iron at the same price (e.g., 4 gold), the system could prioritize based on who listed first or split the order proportionally. This detail would depend on your implementation.
Why It Works
This system mimics a real-world order book (like in stock or commodity markets) but keeps it simple:
Sellers compete to offer the lowest price.
Buyers benefit from getting the best deals within their budget.
The system is transparent: no hidden fees, no haggling, just straightforward matching.
Implementation Notes
the logic is simple:
Collect all seller offers (quantity, price).
Sort offers by price (lowest first).
Iterate through sorted offers, fulfilling the buyer’s quantity as long as the price is ≤ buyer’s maximum.
Calculate costs and update seller payments and buyer’s remaining budget.
This could be implemented in a few lines of code in most programming languages, using basic data structures like lists or arrays.
