103 lines
2.7 KiB
C++
103 lines
2.7 KiB
C++
#include <iostream>
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template <typename T>
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class Node {
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public:
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T data;
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Node *next;
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Node(T data)
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: data(data) , next(nullptr) {};
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Node(){}
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};
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template <typename T>
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class SinglyLinkedList {
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private:
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Node<T>* head;
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public:
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SinglyLinkedList()
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: head(nullptr){}
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void insertAtHead(T data) {
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Node<T> *temp = new Node<T>(data);
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// if head is not pointing to anything then simply point to new node
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if(this->head == nullptr) {
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this->head = temp;
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return;
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}
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// if head is already point at some node
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// first make new node points to head address
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temp->next = this->head;
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// change head point to new node
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this->head = temp;
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}
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void insertAtEnd(T data){
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Node<T> *newNode = new Node<T>(data);
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// if head is not pointing to anything then simply point to new node
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if(this->head == nullptr) {
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this->head = newNode;
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return;
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}
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// if list is not empty, then traverse to the last node using `temp`, then put the address of the new node in the temp->next
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// and finally, make the next of newNode = NULL
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Node<T> *temp = new Node<T>();
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temp = head;
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while(temp->next != NULL){
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temp = temp->next;
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}
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temp->next = newNode;
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newNode->next= NULL;
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}
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T removeAtHead() {
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// if list is empty we can't remove node
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if(this->head == nullptr) {
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std::cout<<"List is Empty"<<std::endl;
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exit(1);
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}
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// save data of node where head is pointed
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T data = this->head->data;
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// save temp pointer to free the memory
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Node<T>* temp_ptr = this->head;
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this->head = this->head->next;
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// free memory
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delete temp_ptr;
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return data;
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}
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void printList() const {
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if(this->head == nullptr) {
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std::cout<<"List is Empty"<<std::endl;
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} else {
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Node<T> *itr = this->head;
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// iterate through list until itr reach to nullptr and print data
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while(itr != nullptr) {
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std::cout<<itr->data<<" ";
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itr = itr->next;
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}
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std::cout<<std::endl;
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}
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}
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};
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int main() {
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SinglyLinkedList<int> l;
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l.insertAtHead(1);
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l.insertAtHead(2);
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l.insertAtHead(3);
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l.insertAtEnd(5);
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l.removeAtHead();
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l.printList();
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return 0;
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}
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