Linked List Lecture Notes PDF

Linked List  Types of Linked List There are several types of linked list including: 1. Singly (Linear) Linked List 2. Doubly Linked List  Doubly Linked Lists A doubly link list is a list in which each node is linked to both its successor a...

Linked List  Types of Linked List There are several types of linked list including: 1. Singly (Linear) Linked List 2. Doubly Linked List  Doubly Linked Lists A doubly link list is a list in which each node is linked to both its successor and its predecessor. Head Pointer Node A Node B Node C Node D 10 20 30 10 A graphical view of a doubly linked list  Doubly linked list - Motivation Doubly linked lists are useful for playing video and sound files with “rewind” and “instant replay”. They are also useful for other linked data which require “rewind” and “fast forward” of the data  Doubly Linked Lists In a Doubly Linked List each item points to both its predecessor and successor next points to the successor prev points to the predecessor Doubly Linked List – Node Definition struct Node{ int data; struct Node* next; struct Node* prev; }; struct Node* head = NULL;  Size int size() { int count = 0; Node* curr = head; while(curr != NULL) { count++; curr = curr->next; } return count; }  Doubly Linked List – insert at first NULL Head NULL prev data next prevdata next data next prev data next prev data next NULL danext newNode //Inserting at first void insertFirst(int data){ Node* newNode = new Node; newNode->data = data; newNode->next = NULL; newNode->prev = NULL; if(head == NULL) { head = newNode; } else { newNode->next = head; head -> prev = newNode; head = newNode; } } Doubly Linked List – insert at last NULL Head NULL prev data next prevdata next data next prev data next data next danext prev NULL newNode //Inserting at Last void insertLast(int data){ Node* newNode = new Node; newNode->data = data; newNode->next = NULL; newNode->prev = NULL; if(head == NULL) { head = newNode; } else { Node* curr = head; while(curr->next != NULL) curr = curr->next; curr->next = newNode; newNode ->prev = curr; } }  Doubly Linked List – insert at middle Head data next prev data next data data next prev prev data next data next prev curr prev data next newNode  Insertion at position void insertAtPos (int data, int pos){ if (pos == 1){ insertFirst(data); return; } else if (pos > size()){ insertLast(data); return; } Node* newNode = new Node; newNode->data = data; newNode->next = NULL; newNode->prev = NULL; int curPos = 1; if(head == NULL) { head = newNode; } else { Node *curr = head; Node *prev = NULL; while(curPos != pos){ prev=curr; curr = curr->next; curPos++; } prev->next = newNode; newNode->prev = prev; newNode->next = curr; curr->prev = newNode; } }  Doubly Linked List – delete Head data next prev data next datadatanext prev next prev data next data ext prev curr  Deletion at position void deleteAtPos(int pos){ if (pos > size()) return; //do nothing Node* curr = head; int curPos = 1; if (head !=NULL) { if(pos ==1){ head = curr->next; head->prev = NULL; delete curr; } else{ Node *prev = NULL; while(curPos != pos){ prev=curr; curr = curr->next; curPos++; } prev->next = curr->next; if (curr ->next != NULL) curr ->next->prev = prev; delete curr; } } }