C++ : Lecture 19: Deletion from Doubly Circular Linked List : Mastering Linked List Made Simple !

 Mastering Linked List Made Simple: Your Easy Guide to Data Structures !

Deletion from Doubly Circular Linked List Code [C++] :

// Shyam Sunder Kanth

// Insta : still_23.6_8

#include<iostream>

using namespace std;

class Node{

    public:

    int data;

    Node* prev;

    Node* next;

    Node(int val){

        this->data = val;

        this->prev = this;

        this->next = this;

    }

};

int length(Node* head, Node* tail){

    Node* temp = head;

    int cnt = 1;

    while(temp != tail){

        temp = temp->next;

        cnt++;

    }

    return cnt;

}

void insert(Node* &head, Node* &tail, int data, int pos){

    // Step 1: creation of newNode

    Node* newNode = new Node(data);

    // Step 2: Handle empty list case

    if(head == NULL){

        head = newNode;

        tail = newNode;

        return;

    }

    // Step 3: Handle non empty list case

    // Sub-1 : insert at beg

    if(pos == 1){

        newNode->next = head;

        newNode->prev = tail;

        head->prev = newNode;

        tail->next = newNode;

        head = newNode;

        return;

    }

    // Sub-2 : insert at end

    int len = length(head,tail);

    if(pos == len+1){

        newNode->next = head;

        newNode->prev = tail;

        head->prev = newNode;

        tail->next = newNode;

        tail = newNode;

        return;

    }

    // Sub-3 : insert at any pos

    Node* p1 = NULL;

    Node* p2 = head;

    int cnt = 1;

    while(cnt < pos){

        p1 = p2;

        p2 = p2->next;

        cnt++;

    }

    newNode->next = p2;

    newNode->prev = p1;

    p1->next = newNode;

    p2->prev = newNode;

}

void deletion(Node* &head, Node* &tail, int pos){

    // Step 1: EMpty list

    if(head == NULL){

        cout<<"List is empty";

        return;

    }

    // Step 2: Non empty list

    // Sub-1 : beginning

    if(pos == 1){

        Node* temp = head;

        head = head->next;

        tail->next = head;

        head->prev = tail;

        temp->next = NULL;

        temp->prev = NULL;

        return;

    }

    // Sub-2

    int len = length(head,tail);

    if(pos == len){

        Node* temp = tail;

        tail = tail->prev;

        tail->next = head;

        head->prev = tail;

        temp->prev = NULL;

        temp->next = NULL;

        return;

    }

    Node* p1 = NULL;

    Node* p2 = head;

    int cnt = 1;

    while(cnt<pos){

        p1 = p2;

        p2 = p2->next;

        cnt++;

    }

    p1->next = p2->next;

    p2->next->prev = p1;

    p2->prev = NULL;

    p2->next = NULL;

}

void print(Node* head){

    if(head == NULL){

        cout<<"List is empty";

        return;

    }

    Node* temp = head;

    cout<<temp->data<<" ";

    while(temp->next != head){

        temp = temp->next;

        cout<<temp->data<<" ";

    }

}

int main()

{

    Node* head = NULL;

    Node* tail = NULL;

    insert(head,tail,5,10);

    insert(head,tail,4,1);

    insert(head,tail,6,3);

    insert(head,tail,7,4);

    insert(head,tail,10,3);

    insert(head,tail,20,2);

    deletion(head,tail,1);

    deletion(head,tail,5);

    deletion(head,tail,3);

    deletion(head,tail,2);

    print(head);

    return 0;

}

Hey, thanks for watching our video about Linked list ! In this video we’ll walk you through:

- Concept

- Deletion in doubly circular linked list

- Steps in deletion

- Cases and subcases

- Code

All codes are available at my GitHub account, check them out here:

https://github.com/shyamkanth/Placements

Check out other videos from DS Revealed playlist: https://www.youtube.com/playlist?list=PLNXqJgOsTCZOB60T9HDhMf_o8RXbNWgqS

Check out our channel here: https://www.youtube.com/@DevelopersByte

Find us at: https://shyamkanth.github.io/

Timestamps:

1:02 Concept

1:55 Approach

6:33 Deletion from beginning

13:01 Code

16:14 Deletion from end

19:52 Code

22:26 Deletion from any position

28:41 Code

31:35 Outro

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