C++ : Lecture 12: Insertion at Any Position in Doubly Linked List : Mastering Linked List Made Simple !

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

Insertion at any position in Doubly Linked List code [C++]:

#include<iostream>

using namespace std;

class Node{

    public:

    int data;

    Node* next;

    Node* prev;

    Node(int val){

        this->data = val;

        this->next = NULL;

        this->prev = NULL;

    }

};

int length(Node* head){

    Node* temp = head;

    int cnt = 1;

    while(temp->next != NULL){

        cnt++;

        temp = temp->next;

    }

    return cnt;

}

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

    // Step 1: Create a new Node

    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

    newNode->next = head;

    head->prev = newNode;

    head = newNode;

}

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

    // Step 1: Create a new Node

    Node* newNode = new Node(data);

    // Step 2: Handle empty list case

    if(head == NULL){

        head = newNode;

        tail = newNode;

        return;

    }

    // Step 3: Non empty list handle

    tail->next = newNode;

    newNode->prev = tail;

    tail = newNode;

}

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

    // Step 1

    Node* newNode = new Node(data);

    // Step 2:

    if(head == NULL){

        head = newNode;

        tail = newNode;

        return;

    }

    // Step 3

    // Subcase 1

    if(pos == 1){

        insertAtBeg(head,tail,data);

        return;

    }

    // Subcase 2

    int len = length(head);

    if(pos == len+1){

        insertAtEnd(head,tail,data);

        return;

    }

    // Subcase 3

    Node* back = NULL;

    Node* front = head;

    int cnt = 1;

    while(cnt<pos){

        back = front;

        front = front->next;

        cnt++;

    }

    newNode->next = front;

    newNode->prev = back;

    back->next = newNode;

    front->prev = newNode;

}

void print(Node* head, Node* tail){

    if(head == NULL){

        cout<<"List is empty."<<endl;

        return;

    }

    Node* temp = head;

    while(temp!=NULL){

        cout<<temp->data<<" ";

        temp=temp->next;

    }

    cout<<endl;

    cout<<"Head: "<<head->data<<endl;

    cout<<"Tail: "<<tail->data<<endl;

}

int main(){

    Node* head = NULL;

    Node* tail = NULL;

    insertAtBeg(head,tail,5);

    insertAtBeg(head,tail,4);

    insertAtEnd(head,tail,6);

    insertAtEnd(head,tail,7);

    insertAtPos(head,tail,1,1);

    insertAtPos(head,tail,8,6);

    insertAtPos(head,tail,2,2);

    insertAtPos(head,tail,3,3);

    print(head,tail);

    

}

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

- Concept

- Insertion at any position

- Cases in insertion

- Subcases in insertion

- Dry run

- 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:

0:00 Intro

0:43 Concept

3:28 Approach

7:05 Subcase-1: insert at beginning

8:07 Subcase-2: insert at end

9:49 Subcase-3: any random position

26:55 Code

31:05 Output

33:43 Outro

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