Merge two sorted linked lists

//{ Driver Code Starts
#include<iostream>
using namespace std;

/* Link list Node */
struct Node
{
    int data;
    struct Node *next;

    Node(int x)
    {
        data = x;
        next = NULL;
    }
};

Node* sortedMerge(struct Node* a, struct Node* b);

/* Function to print Nodes in a given linked list */
void printList(struct Node *n)
{
    while (n!=NULL)
    {
        cout << n->data << " ";
        n = n->next;
    }
    cout << endl;
}

/* Driver program to test above function*/
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n,m;
        cin>>n>>m;

        int data;
        cin>>data;
        struct Node *head1 = new Node(data);
        struct Node *tail1 = head1;
        for (int i = 1; i < n; ++i)
        {
            cin>>data;
            tail1->next = new Node(data);
            tail1 = tail1->next;
        }

        cin>>data;
        struct Node *head2 = new Node(data);
        struct Node *tail2 = head2;
        for(int i=1; i<m; i++)
        {
            cin>>data;
            tail2->next = new Node(data);
            tail2 = tail2->next;
        }

        Node *head = sortedMerge(head1, head2);
        printList(head);
    }
    return 0;
}

// } Driver Code Ends




/* Link list Node
struct Node {
  int data;
  struct Node *next;

  Node(int x) {
    data = x;
    next = NULL;
  }
};
*/
//Function to merge two sorted linked list.
Node* reverseList(Node* head)
{
    if (head->next == NULL)
        return head;
    Node* rest = reverseList(head->next);
    head->next->next = head;
    head->next = NULL;
    return rest;
}

// Given two non-empty linked lists 'a' and 'b'
Node* sortedMerge(Node* a, Node* b)
{
    // Reverse Linked List 'a'
    a = reverseList(a);
    // Reverse Linked List 'b'
    b = reverseList(b);
    // Initialize head of resultant list
    Node* head = NULL;
    Node* temp;
    // Traverse both lists while both of them
    // have nodes.
    while (a != NULL && b != NULL) {
        // If a's current value is greater than or equal to
        // b's current value.
        if (a->data >= b->data) {
            // Store next of current Node in first list
            temp = a->next;
            // Add 'a' at the front of resultant list
            a->next = head;
            // Make 'a' - head of the result list
            head = a;
            // Move ahead in first list
            a = temp;
        }

        // If b's value is greater. Below steps are similar
        // to above (Only 'a' is replaced with 'b')
        else {
            temp = b->next;
            b->next = head;
            head = b;
            b = temp;
        }
    }

    // If second list reached end, but first list has
    // nodes. Add remaining nodes of first list at the
    // beginning of result list
    while (a != NULL) {
        temp = a->next;
        a->next = head;
        head = a;
        a = temp;
    }

    // If first list reached end, but second list has
    // nodes. Add remaining nodes of second list at the
    // beginning of result list
    while (b != NULL) {
        temp = b->next;
        b->next = head;
        head = b;
        b = temp;
    }
    // Return the head of the result list
    return head;
}
 // https://practice.geeksforgeeks.org/problems/merge-two-sorted-linked-lists/