SLL

SLL stands for singly linked list, a basic data structure used to store a collection of elements. In an SLL, each element, or node, contains data and a reference to the next node in the sequence. Access to the list is achieved via a pointer to the head node. Unlike arrays, singly linked lists have dynamic size and do not require contiguous memory, which allows efficient insertions and deletions without resizing.

Structure and variants: Each node stores a data value and a next pointer. A singly linked list may also maintain a tail pointer to enable efficient appends. Some implementations use a sentinel or dummy node to simplify edge cases. A circular singly linked list connects the last node back to the head, forming a closed loop.

Operations and complexity: Common operations include traversal to visit elements in order. Insertion at the head is typically O(1); insertion at the tail is O(n) unless a tail pointer is maintained. Insertion after a given node is O(1) once the previous node is known. Deletion requires access to the preceding node to adjust links, and is generally O(n) if the target node must be searched. Searching for a value is O(n) in a standard singly linked list.

Advantages and limitations: The primary benefits are dynamic size, straightforward implementation, and efficient insertions and deletions at the beginning. Limitations include sequential access rather than direct indexing, the need to traverse to reach non-head positions, additional memory for next pointers, and poorer cache locality compared with contiguous arrays.

Uses and applications: SLLs are used as building blocks for stacks and queues, implementations of adjacency lists in graphs, and foundational components in various data structures and algorithms. They are also employed in memory management tasks where dynamic allocation and pointer-based structures are advantageous.