题目：输入两个递增排序的链表，合并这两个链表并使新链表中的节点依然是排序的

public class MergeNode {
    public ListNode Merge(ListNode pHead1,ListNode pHead2){
        if(pHead1==null) return pHead2;
        if(pHead2==null) return pHead1;
        ListNode pMergeNode = null;
        if(pHead1.val<pHead2.val){
            pMergeNode = pHead1;
            pMergeNode.next = Merge(pHead1.next,pHead2);
        }
        else{
            pMergeNode=pHead2;
            pMergeNode.next=Merge(pHead1,pHead2.next);
        }
        return pMergeNode;
    }
}