Network flow problems involve the movement of items through a network, represented as a graph. In this graph, nodes represent points (like warehouses or destinations), and edges represent paths (like roads or pipelines) that can carry a certain amount of flow. The goal is often to maximize the flow from a source node to a sink node while respecting capacity limits on the edges. These problems are common in various fields, including logistics, telecommunications, and transportation. Algorithms such as the Ford-Fulkerson method or Edmonds-Karp algorithm are used to find optimal solutions, ensuring efficient resource distribution across the network.