Optimal substructure

Optimal substructure is when you have a big problem that can be broken down into smaller parts. Each of the smaller parts can then also be broken down into even smaller parts. This builds up to a structure that can be helpful in solving the big problem. It's like doing a jigsaw puzzle--each piece of the puzzle is smaller than the puzzle itself and when you put it all together it forms the big picture. The same is true in optimal substructure, when you break down the problem into smaller and smaller parts, it helps you to solve the big problem in the most efficient way possible.