Linked List Questions

Author: alisamad1

Linked_List/Implementation_of_Node.cpp

@@ -0,0 +1,17 @@
+#include<iostream>
+using namespace std;
+class Node{
+    public:
+    int data;
+    Node * next;
+    Node(int data){
+        this->data = data;
+        this-> next = NULL;
+    }
+};
+int main(){
+    Node* node1 = new Node(10);
+    cout << node1 -> data  << endl;
+    cout << node1 -> next << endl;
+    return 0;
+}

Linked_List/Insertion_at_linked_list.cpp

@@ -0,0 +1,32 @@
+#include<iostream>
+using namespace std;
+class Node{
+    public:
+    int data;
+    Node * next;
+    Node(int data){
+        this->data = data;
+        this->next = NULL;
+    }
+};
+void InsertionAtHead(Node* &head, int data){
+    Node * node1 = new Node(data);
+    node1->next = head;
+    head = node1;
+}
+void printLinkedList(Node* head){
+    while(head != NULL){
+        cout << head->data << " ";
+        head = head->next;
+    }
+    cout << endl;
+}
+int main(){
+    Node * node1 = new Node(10);
+    cout << "Initial Linked List: "; 
+    printLinkedList(node1);
+    InsertionAtHead(node1, 20);
+    cout << "Linked List after insertion at head: ";
+    printLinkedList(node1);
+    return 0;
+}

Linked_List/circular_linked_list.cpp

@@ -0,0 +1,140 @@
+#include<iostream>
+#include<map>
+using namespace std;
+class Node {
+    public:
+    int data;
+    Node* next;
+    //constrcutor
+    Node(int d) {
+        this->data = d;
+        this->next = NULL;
+    }
+    ~Node() {
+        int value = this->data;
+        if(this->next != NULL) {
+            delete next;
+            next = NULL;
+        }
+        cout << " memory is free for node with data " << value << endl;
+    }
+};
+void insertNode(Node* &tail, int element, int d) {
+    //empty list
+    if(tail == NULL) {
+        Node* newNode = new Node(d);
+        tail = newNode;
+        newNode -> next = newNode;
+    }
+    else{
+        //non-empty list
+        //assuming that the element is present in the list
+        Node* curr = tail;
+        while(curr->data != element) {
+            curr = curr -> next;
+        }
+        //element found -> curr is representing element wala node
+        Node* temp = new Node(d);
+        temp -> next = curr -> next;
+        curr -> next = temp;
+    }
+}    
+void print(Node* tail) {
+    Node* temp = tail;
+    //empty list
+    if(tail == NULL) {
+        cout << "List is Empty "<< endl;
+        return ;
+    }
+    do {
+        cout << tail -> data << " ";
+        tail = tail -> next;
+    } while(tail != temp);
+    cout << endl;
+} 
+void deleteNode(Node* &tail, int value) {
+    //empty list
+    if(tail == NULL) {
+        cout << " List is empty, please check again" << endl;
+        return;
+    }
+    else{
+        //non-empty
+        //assuming that "value" is present in the Linked List
+        Node* prev = tail;
+        Node* curr = prev -> next;
+        while(curr -> data != value) {
+            prev = curr;
+            curr = curr -> next;
+        }
+        prev -> next = curr -> next;
+        //1 Node Linked List
+        if(curr == prev) {
+            tail = NULL;
+        }
+        //>=2 Node linked list
+        else if(tail == curr ) {
+            tail = prev;
+        }
+        curr -> next = NULL;
+        delete curr;
+    }
+}
+bool isCircularList(Node* head) {
+    //empty list
+    if(head == NULL) {
+        return true;
+    }
+    Node* temp = head -> next;
+    while(temp != NULL && temp != head ) {
+        temp = temp -> next;
+    }
+    if(temp == head ) {
+        return true;
+    }
+    return false;
+}
+bool detectLoop(Node* head) {
+    if(head == NULL)
+        return false;
+    map<Node*, bool> visited;
+    Node* temp = head;
+    while(temp !=NULL) {
+        //cycle is present
+        if(visited[temp] == true) {
+            return true;
+        }
+        visited[temp] = true;
+        temp = temp -> next;
+    }
+    return false;
+}
+int main() {
+    Node* tail = NULL;
+   // insertNode(tail, 5, 3);
+    //print(tail);
+  //  insertNode(tail, 3, 5);
+   // print(tail);
+/*
+    insertNode(tail, 5, 7);
+    print(tail);
+    insertNode(tail, 7, 9);
+    print(tail);
+    insertNode(tail, 5, 6);
+    print(tail);
+    insertNode(tail, 9, 10);
+    print(tail);
+    insertNode(tail, 3, 4);
+    print(tail);
+    deleteNode(tail, 5);
+    print(tail);
+     */
+    if(isCircularList(tail)) {
+        cout << " Linked List is Circular in nature" << endl;
+    }
+    else{
+        cout << "Linked List is not Circular " << endl;
+    }
+
+    return 0;
+}

Linked_List/doublyLinked_List.cpp

@@ -0,0 +1,158 @@
+#include<iostream>
+using namespace std;
+class Node {
+    public:
+    int data;
+    Node* prev;
+    Node* next;
+    //constructor
+    Node(int d ) {
+        this-> data = d;
+        this->prev = NULL;
+        this->next = NULL;
+    }
+    ~Node() {
+        int val = this -> data;
+        if(next != NULL) {
+            delete next;
+            next = NULL;
+        }
+        cout << "memory free for node with data "<< val << endl;
+    }
+};
+//traversing a linked list
+void print(Node* head) {
+    Node* temp  = head ;
+    while(temp != NULL) {
+        cout << temp -> data << " ";
+        temp  = temp -> next;
+    }
+    cout << endl;
+}
+//gives length of Linked List
+int getLength(Node* head) {
+    int len = 0;
+    Node* temp  = head ;
+    while(temp != NULL) {
+        len++;
+        temp  = temp -> next;
+    }
+    return len;
+}
+void insertAtHead(Node* &tail, Node* &head, int d) {
+    //empty list
+    if(head == NULL) {
+        Node* temp = new Node(d);
+        head = temp;
+        tail = temp;
+    }
+    else{
+        Node* temp = new Node(d);
+        temp -> next = head;
+        head -> prev = temp;
+        head = temp;
+    }
+
+}
+void insertAtTail(Node* &tail,Node* &head, int d) {
+    if(tail == NULL) {
+        Node* temp = new Node(d);
+        tail = temp;
+        head = temp;
+    }
+    else{
+        Node* temp = new Node(d);
+        tail -> next  = temp;
+        temp -> prev = tail;
+        tail = temp;
+    }
+}
+void insertAtPosition(Node* & tail, Node* &head, int position, int d) {
+    //insert at Start
+    if(position == 1) {
+        insertAtHead(tail,head, d);
+        return;
+    }
+    Node* temp  = head;
+    int cnt = 1;
+    while(cnt < position-1) {
+        temp = temp->next;
+        cnt++;
+    }
+    //inserting at Last Position
+    if(temp -> next == NULL) {
+        insertAtTail(tail,head,d);
+        return ;
+    }
+    //creating a node for d
+    Node* nodeToInsert = new Node(d);
+    nodeToInsert ->next = temp -> next;
+    temp -> next -> prev = nodeToInsert;
+    temp -> next = nodeToInsert;
+    nodeToInsert -> prev = temp;
+}
+void deleteNode(int position, Node* & head) { 
+    //deleting first or start node
+    if(position == 1) {
+        Node* temp = head;
+        temp -> next -> prev = NULL;
+        head = temp ->next;
+        temp -> next = NULL;
+        delete temp;
+    }
+    else
+    {
+        //deleting any middle node or last node
+        Node* curr = head;
+        Node* prev = NULL;
+        int cnt = 1;
+        while(cnt < position) {
+            prev = curr;
+            curr = curr -> next;
+            cnt++;
+        }
+        curr -> prev = NULL;
+        prev -> next = curr -> next;
+        curr -> next = NULL;
+        delete curr;
+    }
+}
+int main() {
+    Node* head = NULL;
+    Node* tail = NULL;
+    print(head);
+    //cout << getLength(head) << endl;
+    insertAtHead(tail,head, 11);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    insertAtHead(tail,head, 13);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    insertAtHead(tail,head, 8);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    insertAtTail(tail,head, 25);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    insertAtPosition(tail, head, 2, 100);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    insertAtPosition(tail, head, 1, 101);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    insertAtPosition(tail, head, 7, 102);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    deleteNode(7, head);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+    return 0;
+}