Traveling purchaser problem

The traveling purchaser problem (TPP) is an NP-hard problem studied in operations research and theoretical computer science. Given a list of marketplaces, the cost of travelling between different marketplaces, and a list of available goods together with the price of each such good at each marketplace, the task is to find, for a given list of articles, the route with the minimum combined cost of purchases and traveling.

Source: Wikipedia — Traveling purchaser problem (CC BY-SA 4.0)