mregeSortedLInkedListRuntimeerroe.cpp

#include<iostream>

using namespace std;

class Node{
public:
    int data;
    Node* next;
    
    Node(int x)
    {
        data = x;
        next = NULL;
    }
};


Node* createLL(int n)
{
    Node* head = NULL;
    Node* tail = NULL;
    
    int i = 0;
    
    while(i!=n)
    {
        int x;
        cin>>x;
        
        Node* cur = new Node(x);
        
        if(head == NULL)
        {
            head = cur;
            tail = cur;
        }
        
        else
        {
            tail->next = cur;
            tail = cur;
        }
        i++;
    }
    
    return head;
}

void display(Node* head){
    Node* cur = head;
    while(cur != NULL){                 // while(cur)
        cout << cur->data << " ";
        cur = cur->next;
    }
}

Node* mergeSortedLL(Node* head1, Node* head2)
{
    Node* head = NULL;
    Node* cur = NULL;
    Node* tail = NULL;
    
    int ele1=0,ele2=0;
    
    if(head1)
    ele1 = head1->data;
    
    if(head2)
    ele2 = head2->data;
    
    while(head1 && head2)
    {
        if(ele2 > ele1)
        {
            cur = new Node(ele1);
            
            if(head == NULL)
            {
                head = cur;
                tail = cur;
            }
            else
            {
                tail->next = cur;
                tail = cur;
            }
            
            if(head1->next==NULL)
                break;
            
            head1 = head1->next;
            ele1 = head1->data;
        }
        else
        {
            cur = new Node(ele2);
            
            if(head == NULL)
            {
                head = cur;
                tail = cur;
            }
            else
            {
                tail->next = cur;
                tail = cur;
            }
            
            if(head2->next == NULL)
                break;
            head2 = head2->next;
            ele2 = head2->data;
        }
        
    }
    
    if(head1 && head2->next==NULL)
    {
        while(head1)
        {
            tail->next = head1;
            tail = head1;
            head1 = head1->next;
        }
    }
    
    else if(head2 && head1->next == NULL)
    {
        while(head2)
        {
            tail->next = head2;
            tail = head2;
            head2 = head2->next;
        }
    }
    
    
        return head;
    
}



int main()
{
    int t;
    cin>>t;
    
    while(t!=0) {
    int n;
    cin>> n;
    Node* head1 = createLL(n);
    
    int m;
    cin>> m;
    Node* head2 = createLL(m);
    
    Node* head = mergeSortedLL(head1, head2);
    display(head);
        
        t--;
    }
}