Finding middle element in a linked list.cpp

//{ Driver Code Starts
// Initial template for C++

#include <bits/stdc++.h>
using namespace std;

struct Node
{
    int data;
    struct Node *next;

    Node(int x)
    {
        data = x;
        next = NULL;
    }
};
void printList(Node *node)
{
    while (node != NULL)
    {
        cout << node->data << " ";
        node = node->next;
    }
    cout << "\n";
}

// } Driver Code Ends
/* Link list Node
struct Node {
    int data;
    Node* next;

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

}; */
class Solution
{
public:
    /* Should return data of middle node. If linked list is empty, then  -1*/
    int getMiddle(Node *head)
    {
        // Your code here

        if (head == NULL)
            return -1;

        if (head->next == NULL)
            return head->data;

        if (head->next->next == NULL)
            return head->next->data;

        Node *slow = head;
        Node *fast = head->next;

        while (fast != NULL)
        {

            fast = fast->next;

            if (fast != NULL)
            {
                fast = fast->next;
            }

            slow = slow->next;
        }

        return slow->data;
    }
};

//{ Driver Code Starts.

int main()
{
    // code
    int t;
    cin >> t;
    while (t--)
    {
        int N;
        cin >> N;
        int data;
        cin >> data;
        struct Node *head = new Node(data);
        struct Node *tail = head;
        for (int i = 0; i < N - 1; ++i)
        {
            cin >> data;
            tail->next = new Node(data);
            tail = tail->next;
        }

        Solution ob;
        cout << ob.getMiddle(head) << endl;
    }
    return 0;
}

// } Driver Code Ends