LLD Data Structures in Design Context: Why Some Problems Are About Relationships, Not Individual Objects

In LLD, experienced engineers identify Graph problems when business requirements revolve around exploring relationships rather than individual objects. While HashMaps, Heaps, Queues, Stacks, and Tries solve specific object-based challenges, Graphs organize connected entities to support relationship traversal. The critical engineering skill involves recognizing when a business context naturally calls for relationship-based modeling. Instead of focusing on data structures first, designers must start with the business logic to determine if the problem is driven by connectivity.