Sparse array

A sparse array is like a regular array, but with a lot of empty spots. Imagine a shelf with a lot of drawers, but a lot of the drawers are empty. That's like a sparse array. Instead of having things in all of the drawers, there are only things in some of the drawers, and the other drawers are empty. Sparse arrays are more efficient and easier to work with than regular arrays, because you don't have to worry about the empty drawers (or empty spots).