struct ListNode* mergeTwoLists(struct ListNode *l1,struct ListNode *l2){    if(l1==NULL) return l2;    if(l2==NULL) return l1;    if(l1->val
     
      val)    {        l1->next=mergeTwoLists(l1->next,l2);        return l1;    }    else    {        l2->next=mergeTwoLists(l1,l2->next);        return l2;    }}struct ListNode* mergeKLists(struct ListNode** lists, int listsSize) {    if(listsSize==0) return NULL;    while(listsSize!=1)    {        int k=0;        for(int i=0;i