Merge K sorted linked lists

class Solution{
  public:
    //Function to merge K sorted linked list.
   Node* sortedMerge(Node* head1, Node* head2)
{
    // code here
   if(head1==NULL) return head2;
   if(head2==NULL) return head1;

   Node *head=NULL,*tail=NULL;
   if(head1->data<=head2->data){
       head=tail=head1;
       head1=head1->next;
   }else {
       head=tail=head2;
       head2=head2->next;
   }
   while(head1!=NULL && head2!=NULL){
       if(head1->data<=head2->data){
           tail->next=head1;
           head1=head1->next;
       }else {
           tail->next=head2;
           head2=head2->next;
       }
       tail=tail->next;
   }
   if(head1==NULL) tail->next=head2;
   if(head2==NULL) tail->next=head1;
   return head;
}
    Node * mergeKLists(Node *arr[], int K)
    {
           // Your code here
           Node *curr=arr[0];
          for(int i=1;i<K;i++){
               curr=sortedMerge(curr,arr[i]);
          }
           return curr;
    }
};