Linked lists are a fundamental data structure in computer science that consist of a sequence of nodes, where each node contains data and a pointer (or reference) to the next node in the sequence. This structure allows for dynamic memory allocation, meaning that linked lists can grow or shrink in size as needed during runtime, unlike arrays, which have a fixed size determined at the time of declaration. Linked lists come in various forms, including singly linked lists, doubly linked lists, and circular linked lists. In a singly linked list, each node points to the next node, while in a doubly linked list, each node has pointers to both the next and previous nodes, allowing for bidirectional traversal. Circular linked lists connect the last node back to the first node, forming a loop. One of the primary advantages of linked lists over arrays is the ease of insertion and deletion operations. In linked lists, these operations can be performed in constant time O(1) when inserting or removing nodes at the beginning or end of the list, while in arrays, shifting elements is often required, leading to a time complexity of O(n). However, linked lists have drawbacks, including increased memory usage due to the storage of pointers and the lack of direct access to elements, which can lead to slower search times (O(n)) compared to arrays, where access time is O(1). Understanding the differences between linked lists and arrays is essential for mastering data structures and algorithms, as each structure has its unique strengths and weaknesses, making them suitable for different applications.