Data Structures And Algorithms

Linear Data Structures

Linear data structures organize data in a sequential order, where elements are arranged one after the other. This makes them easy to traverse from the first element to the last. Each element is directly connected to its next and/or previous element, depending on the structure.

These are ideal when data needs to be processed in the order it’s received or stored.

1. Arrays

An array is a collection of elements stored in contiguous memory locations. Each element in an array is accessed by its index, and all elements must be of the same data type in most languages.

Example:

Use cases:

• Fast access to elements using an index

• Useful for storing fixed-size data like exam scores or sensor readings

Limitations:

• Fixed size once declared

• Inserting or deleting elements is inefficient

ProTip:
Use arrays when you know the exact number of elements in advance and need fast, random access. Avoid them for tasks requiring frequent insertions or deletions.

2. Linked Lists

A linked list is a dynamic structure made up of nodes. Each node contains data and a reference to the next node in the sequence. Unlike arrays, linked lists don’t require contiguous memory.

Example:

Use cases:

• Useful when the number of elements is unknown or changes frequently

• Insertion and deletion are efficient, especially at the beginning or middle

Limitations:

• Slower access to elements (no indexing)

• More memory usage due to storage of pointers

ProTip:
Choose linked lists when your application involves frequent insertions and deletions, especially in unpredictable positions.

3. Stacks

A stack is a Last In First Out (LIFO) structure. The last element added is the first one removed. Think of it like a pile of plates.

Example:

Operations:

• push(): adds an element to the top

• pop(): removes the top element

• peek(): shows the top element without removing it

Use cases:

• Undo operations in software

• Expression evaluation

• Function call management in recursion

ProTip:
Use stacks for problems where data needs to be reversed or where the most recent entry should be processed first.

4. Queues

A queue is a First In First Out (FIFO) structure. The first element added is the first one to be removed. It operates like a line at a ticket counter.

Example:

Types of queues:

• Simple Queue

• Circular Queue

• Priority Queue

• Double-Ended Queue (Deque)

Use cases:

• Task scheduling

• Printer queues

• Real-time messaging

ProTip:
Use queues when the order of processing matters, such as handling tasks, managing threads, or delivering notifications.