Data Structures Notes

 Data Structures Notes

• Arrays are a linear data structure that store elements in a contiguous block of memory. They are easy to implement and access, but they can be inefficient for storing large amounts of data or for dynamic data structures.
• Linked lists are a linear data structure that store elements in a linked list of nodes. Each node contains a data element and a pointer to the next node in the list. Linked lists are more efficient than arrays for storing large amounts of data or for dynamic data structures, but they can be more difficult to implement and access.
• Stacks are a linear data structure that follows the last-in, first-out (LIFO) principle. Elements are added to the stack at the top and removed from the top. Stacks are often used to implement functions like undo and redo.
• Queues are a linear data structure that follows the first-in, first-out (FIFO) principle. Elements are added to the queue at the rear and removed from the front. Queues are often used to implement data structures like priority queues.
• Hash tables are a non-linear data structure that store elements in a hash table. Each element is assigned a hash code, which is used to determine the index of the element in the hash table. Hash tables are very efficient for searching, but they can be less efficient for insertion and deletion

Data Structure	Type	Access Order	Applications
Stack	Linear	LIFO	Backtracking, Undo, call stack, Page-visited history
Queue	Linear	FIFO	Simulation, Printer queue, Process scheduling, GUI event
Tree	Non-linear	Hierarchical	Decision processes, File system, binary search, Arithmetic expressions
Graph	Non-linear	Any	Social network, shortest path, minimum spanning tree, Transportation and Computer networks, ERD

Data structure	Description	Access	Advantages	Disadvantages
Stack	LIFO (last in, first out) data structure	Top element	Easy to implement, efficient for operations that only need to access the top element	Can only access the top element
Queue	FIFO (first in, first out) data structure	Front element	Easy to implement, efficient for operations that only need to access the front element	Can only access the front element
Linked list	Linear data structure	Any element	Flexible and efficient for operations that need to access any element in the list	Can be inefficient for some operations, such as inserting and deleting elements in the middle of the list
Graph	Non-linear data structure	Any vertex	Flexible and powerful for modeling relationships between objects	Can be difficult to implement and manage
Hash table	Maps keys to values	Key	Fast lookups	Can be inefficient for some operations, such as inserting and deleting elements

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