LinkedList-VJ-V2.pptx Analysis of Algorithms and Data Structures
- 1. LinkedList
- 2. LinkedList • A linked list is a non-primitive linear data structure, in which the elements are not stored at contiguous memory locations. • It is a collection of items and each item is represented by a node.
- 3. Cont… • Each node will contain at least two field. • First field will contain information of element is called data and this field also called data field. • Second field is called pointer field and it will contain the address of next node.
- 4. Cont… • Here, we will have a START pointer that will contain the address of first node of a linkedlist.
- 5. Types of LinkedList • There are different types of linkedlist. • Single LinkedList (Linear LinkedList) • Circular Single LinkedList • Doubly LinkedList • Circular Doubly LinkedList
- 6. 1. Single LinkedList (Linear LinkedList) • In it, each node will contain 2 fields. • First field will contain the information of the element is called data field and second field contain the address of next node is called pointer field. • Pointer field of last node will contain NULL value.
- 7. Example of Single LinkedList 100 START info next 100 info next 200 info next 300 10 200 20 300 30 NULL
- 8. Disadvantage of Single Linked List • In it, we can not access previous node from the current node. • This problem can be removed in doubly LinkedList.
- 9. Operations on Linked List • Following are important operations on Linked List • Inserting Element in a linked list • Traversing/Processing/Printing a Linked List • Deleting Element from a linked list • Count number of elements in a linked list • Search an element in a linked list
- 10. Operations on Linked List • Following are important operations on Linked List • Insert • Traverse • Delete • Count • Search
- 11. Traverse • Traversal of Singly Linked List • Traversal in a linked list means visiting each node and performing operations like printing or processing data.
- 12. Traverse • Step-by-step approach: 1. Initialize a pointer (current) to the head of the list. 2. Loop through the list using a while loop until current becomes NULL. 3. Process each node (e.g., print its data). 4. Move to the next node by updating current = current->next.
- 14. Search • Searching in Singly Linked List • Searching in a Singly Linked List refers to the process of looking for a specific element or value within the elements of the linked list.
- 15. Search • Step-by-step approach: 1. Start from the head of the linked list. 2. Check each node’s data: 3. If it matches the target value, return true (element found). 4. Otherwise, move to the next node. 5. Repeat until the end (NULL) is reached. 6. If no match is found, return false.
- 17. Count/Length • Length of Singly Linked List • Finding the length of a Singly Linked List means counting the total number of nodes.
- 18. Count/Length • Step-by-step approach: • Initialize a counter (length = 0). • Start from the head, assign it to current. • Traverse the list: • Increment length for each node. • Move to the next node (current = current->next). • Return the final length when current becomes NULL.
- 20. Delete • Deletion in Singly Linked List • Deleting a node in a Linked List is an important operation and can be done in three main ways: • removing the first node, • removing a node in the middle, • or removing the last node.
- 21. Delete • There are different scenarios for deletion: • Deletion at the Beginning of Singly Linked List: • Deletion at the End of Singly Linked List: • Deletion at a Specific Position of Singly Linked List:
- 25. Algorithm
- 26. Algorithm is to delete a node containing a specified key Purpose: The purpose of this algorithm is to delete a node containing a specified key value from a singly linked list. The algorithm traverses the list to locate the node with the target value and removes it while maintaining the integrity of the linked list. Problem Statement: Given a singly linked list and a key value, delete the node that contains the specified key. Update the list and ensure all pointers are correctly adjusted.
- 27. Input: A pointer to the head of the linked list. An integer key that represents the value of the node to be deleted. Output: The modified linked list after deleting the node with the given key. If the key is not found, the list remains unchanged. Constraints: The list may be empty. The key may be located anywhere in the list. The node to be deleted may be the first, middle, or last node. Algorithm is to delete a node containing a specified key
- 28. Algorithm: Step 1: Start Define a function deleteNode(head, key) that takes the head of the list and the key as arguments. Step 2: Check if List is Empty If head == null, print "List is empty" and return head. Step 3: Check if Head Node Holds the Key Check if the head node contains the key: If head.data == key, update the head pointer to the next node using: head = head.next Return the updated list. Algorithm is to delete a node containing a specified key
- 29. Step 4: Initialize Pointers Create two pointers: prev → Points to null initially. current → Points to head. Step 5: Traverse the List to Find the Key Loop through the list until current != null: If current.data == key: Update the next pointer of the previous node: prev.next = current.next Break the loop and delete the node. Else: Move prev to current. Move current to current.next. Algorithm is to delete a node containing a specified key
- 30. Algorithm is to delete a node containing a specified key Step 6: Check if Key was Found If the key was not found (current == null), print "Key not found" and return head. Step 7: Return Updated List Return the modified list with the node deleted.
- 31. Algorithm is to delete a node containing a specified key Pseudocode: Function deleteNode(head, key): If head == NULL: Print "List is empty" Return head If head.data == key: head = head.next Return head prev ← NULL current ← head While current != NULL: If current.data == key: prev.next = current.next Break prev ← current current ← current.next If current == NULL: Print "Key not found" Return head
- 32. Insert • Insertion is a fundamental operation in linked lists that involves adding a new node to the list. There are several scenarios for insertion: • Insertion at the Beginning of Singly Linked List: • Insertion at the End of Singly Linked List: • Insertion at a Specific Position of the Singly Linked List:
- 36. Algorithm to Insert node • The purpose of this algorithm is to insert a node with a given key value at a specified position in a singly linked list. The node can be inserted: • At the beginning. • At a specific position. • At the end if the position exceeds the length of the list.
- 37. Input: •A pointer to the head of the linked list. •An integer key representing the value to be inserted. •An integer position representing the 0-based index where the node should be inserted. Algorithm to Insert node in a Linked List Output: •The modified linked list after inserting the new node at the specified position. •If the position is invalid, the list remains unchanged, and an appropriate message is printed.
- 38. Algorithm to Insert node in a Linked List Constraints: The list may be empty. If position == 0, the node is inserted at the beginning. If position > length of list, the node is inserted at the end. Position cannot be negative.
- 39. Algorithm to Insert node in a Linked List Step 1: Start Define a function insertAtPosition(head, key, position) that takes the head of the list, the key, and the position as arguments. Step 2: Check for Invalid Position If position < 0, print: "Invalid position" Return head. Step 3: Create a New Node Allocate memory for a new node. Set: newNode.data = key newNode.next = NULL
- 40. Algorithm to Insert node in a Linked List Step 5: Traverse the List to Find the Position Create a pointer temp and initialize it to head. Initialize a counter count = 0. Traverse the list while temp != NULL and count < position - 1: Move temp to temp.next. Increment count. Step 6: Check if Position is Out of Bounds If temp == NULL and position > count + 1 print: "Position out of bounds, inserting at the end" Traverse to the last node and insert the new node at the end.
- 41. Algorithm to Insert node in a Linked List Step 7: Insert Node at Desired Position If temp != NULL: Update pointers to insert newNode: newNode.next = temp.next temp.next = newNode Step 8: Return Updated List Return the modified list after inserting the node.
- 42. Pseudocode: Function insertAtPosition(head, key, position): If position < 0: Print "Invalid position" Return head Create newNode newNode.data = key newNode.next = NULL If position == 0: newNode.next = head head = newNode Return head temp ← head count ← 0 While temp != NULL AND count < position - 1: temp ← temp.next count ← count + 1 If temp == NULL: Print “Inserting at the end" temp ← head While temp.next != NULL: temp ← temp.next temp.next = newNode Return head newNode.next = temp.next temp.next = newNode Return head
- 43. 2. Circular Single LinkedList • A single linkedlist can be made as circular single linkedlist in which pointer field of last node will contain the address of first node.
- 44. Example of Circular Single LinkedList 100 START info next 100 info next 200 info next 300 10 200 20 300 30 100
- 45. Advantage of Circular Single LinkedList • In it, from last node we can move directly to the first node of circular single LinkedList because pointer field of last node will contain the address of first node.
- 46. Disadvantage of Circular Single Linked List • In it, we can not access previous node from the current node. • This problem can be removed in doubly LinkedList.
- 47. 3. Doubly LinkedList • It is also called Two-way linked list. • Here each node will contain 3 fields. First field will contain the address of previous node. It is also called previous pointer. • Second field will contain the information of element is called data field.
- 48. Cont… • Third field will contain the address of next node is called next pointer.
- 49. Example of Doubly LinkedList 100 prev info next NULL 200 10 200 prev info next 100 300 20 100 300 prev info next 200 NULL 30 START
- 50. Advantage of Doubly LinkedList • In it, we can we can move previous and next node from the current node because every node contain the address of previous and next node.
- 51. Disadvantage of Doubly LinkedList • Doubly LinkedList require more memory than single linkedlist because every node of it contain 3 field. Two pointer and one data field.
- 52. 4. Circular Doubly LinkedList • A doubly linkedlist can be made as circular doubly linkedlist in which the previous pointer of first node will contain the address of last node and next pointer of last node will contain the address of first node.
- 53. Example of Circular Doubly LinkedList 100 prev info next 300 200 10 200 prev info next 100 300 20 100 300 prev info next 200 100 30 START
- 54. Advantage of Circular Doubly LinkedList • In it, from first node we can move directly to the last node because previous pointer of first node will contain the address of last node. • In it, from last node we can move directly to the first node because next pointer of last node will contain the address of first node.
- 55. Advantage of LinkedList • LinkedList is a dynamic data structure i.e they can increase or decrease a node during the execution of a program. • The size is not fixed. • Data can store non-continuous memory block.
- 56. Cont… • Insertion and deletion of a node are easier and efficient.
- 57. Disadvantage of LinkedList • More Memory Required: In the linked list there is an special field called pointer field which hold the address of next node so linked list requires extra space. • Accessing to random data item is time consuming.
- 58. Syntax to create a node of LinkedList struct structure name { datatype variablename; struct structure name *pointervariablename; }; Example: struct node { int info; struct node *next; };
- 59. Cont… Example: struct node { int info; struct node *next; };
- 60. References • Text • https://www.geeksforgeeks.org/singly-linked-list-tutorial/ • https://www.geeksforgeeks.org/linked-list-data-structure/?ref=lbp •