Create Doubly Linked List.cpp

Linkedlist🤐/Doubly Linked List.cpp

@@ -0,0 +1,160 @@
+#include <bits/stdc++.h>
+using namespace std;
+class Node{
+    public:
+    int data;
+    Node* next;
+    Node* back;
+    public:
+    Node(int data1, Node* next1, Node* back1){
+        data = data1;
+        next = next1;
+        back = back1;
+    }
+    public:
+    Node(int data1){
+        data = data1;
+        next = nullptr;
+        back = nullptr;
+    }
+};
+Node* convertArr2DLL(vector<int> arr){
+    Node* head = new Node(arr[0]);
+    Node* prev = head;
+    for(int i=1 ; i<arr.size() ; i++){
+        Node* temp = new Node(arr[i],nullptr,prev);
+        prev->next=temp;
+        prev = temp;
+    }
+    return head;
+}
+void print(Node* head){
+    while(head != NULL){
+        cout << head->data << " ";
+        head = head->next;
+    }
+}
+Node* deleteHead(Node* head){
+    if(head==NULL || head->next==NULL) return NULL;
+    Node* prev = head;
+    head = head->next;
+    head->back = nullptr;
+    prev->next = nullptr;
+    delete(prev);
+    return head;
+}
+Node* deleteTail(Node* head){
+    if(head==NULL || head->next==NULL) return NULL;
+    Node* tail = head;
+    while(tail->next != NULL){
+        tail = tail->next;
+    }
+    Node* prev = tail->back;
+    prev->next=nullptr;
+    tail->back=nullptr;
+    delete(tail);
+    return head;
+}
+Node* removeKthelement(Node* head , int k){
+    if(head==NULL){
+        return NULL;
+    }
+    int cnt=0;
+    Node* temp = head;
+    while(temp!=NULL){
+        cnt++;
+        if(cnt==k) break;
+        temp = temp->next;
+    }
+    Node* prev = temp->back;
+    Node* front = temp->next;
+    if(prev==NULL && front==NULL){
+        return NULL;
+    }
+    else if(prev==NULL){
+        return deleteHead(head);
+    }
+    else if(front==NULL){
+        return deleteTail(head);
+    }
+    prev->next = front;
+    front->back = prev;
+    temp->next = temp->back = nullptr;
+    delete(temp);
+    return head;
+}
+void deleteNode(Node* temp){
+    Node* prev = temp->back;
+    Node* front = temp->next;
+    if(front==NULL){
+        prev->next = nullptr;
+        temp->back = nullptr;
+        delete(temp);
+        return;
+    }
+    prev->next = front;
+    front->back = prev;
+    temp->next = temp->back = nullptr;
+    delete(temp);
+}
+Node* insertBeforeHead(Node* head, int val){
+    Node* newHead = new Node(val,head,nullptr);
+    head->back = newHead;
+    return newHead;
+}
+Node* insertBeforeTail(Node* head, int val){
+    if(head==NULL){
+        return new Node(val);
+    }
+    if(head->next==NULL){
+        return insertBeforeHead(head , val);
+    }
+    Node* tail = head;
+    while(tail->next != NULL){
+        tail = tail->next;
+    }
+    Node* prev = tail->back;
+    Node* newNode = new Node(val,tail,prev);
+    prev->next= newNode;
+    tail->back = newNode;
+    return head;
+}
+Node* insertBeforeKthElement(Node* head, int val , int k){
+    if(k==1){
+        return insertBeforeHead(head , val);
+    }
+    int cnt=0;
+    Node* temp = head;
+    while(temp != NULL){
+        cnt++;
+        if(cnt==k) break;
+        temp = temp->next;
+    }
+    Node* prev = temp->back;
+    Node* newNode = new Node(val,temp,prev);
+    prev->next = newNode;
+    temp->back = newNode;
+    return head;
+}
+void insertBeforeNode(Node* node , int val){
+    Node* prev = node->back;
+    Node* newNode = new Node(val,node,prev);
+    prev->next = newNode;
+    node->back = newNode;
+}
+Node* insertAtTail(Node* head, int val){
+    if(head==NULL) return new Node(val);
+    Node* tail = head;
+    while(tail->next != NULL){
+        tail = tail->next;
+    }
+    Node* newNode = new Node(val,nullptr,tail);
+    tail->next = newNode;
+    return head;
+}
+int main(){
+    vector<int> arr = {12,5,8,7};
+    Node* head = convertArr2DLL(arr);
+    head = insertAtTail(head , 10);
+    print(head);
+}