What is a linked list best described as?

• A. A fundamental data structure that stores data in contiguous memory blocks to enable fast random access.
• B. A data structure that organizes data sequentially, using nodes connected by pointers to allow dynamic size.
• C. A tree-based structure where each node has multiple children.
• D. A hash-based structure that maps keys to values.

Answer: (B)

A linked list is a data structure that stores items in separate nodes linked together by pointers. Each node holds its data and a reference to the next node, so the list can grow or shrink by adjusting these links. Because the nodes don’t have to be in contiguous memory, a linked list can expand dynamically without needing to move other elements.

One key implication is how you access elements: to reach a particular position, you typically start at the head and follow pointers from node to node, which makes random access slower than in contiguous structures like arrays. This trade-off—dynamic size and easy insertion/deletion at ends or in the middle versus slower indexed access—is what characterizes a linked list.

Other structures described in the options don’t fit: a contiguous-memory structure that supports fast random access points to an array, a tree-based structure has multiple branches, and a hash-based structure maps keys to values.