Array Vs Linked List

 

Array

An array is a collection of elements stored in contiguous memory locations, all of the same data type. It allows direct access to elements using their index (O(1) time). Arrays have a fixed size (in static arrays) or require costly resizing (in dynamic arrays). They are memory-efficient but less flexible for frequent insertions and deletions due to the need for shifting elements.

Linked List

A linked list is a collection of nodes, where each node contains data and a pointer (or reference) to the next node. Memory allocation is non-contiguous, allowing the list to grow or shrink easily without reallocation. Access is sequential (O(n) time), but insertions and deletions at known positions can be done efficiently (O(1) if the pointer is available). Linked lists have more memory overhead due to storage of pointers.

Aspect	Array	Linked List
Memory Allocation	Contiguous memory block (static or dynamic size)	Non-contiguous memory; each node has data + pointer(s)
Access Time	O(1) random access via index	O(n) sequential access (must traverse nodes)
Insertion/Deletion	Costly (O(n)) due to shifting elements	Efficient at known positions (O(1) with pointer), but O(n) if traversal needed
Memory Overhead	Minimal (only data storage)	Higher (extra pointer(s) per node)
Resizing	Fixed size (static array) or costly reallocation (dynamic array)	Flexible; grows/shrinks easily without reallocation