用递归把两个有序链表合成一个有序链表

递归

package lhh.fight.LinkTest;

public class SingleLinkMerge
{
    static class ListNode
    {
        int data;
        ListNode next;
        public ListNode(){}
        public ListNode(int data)
        {
            this.data = data;
        }
    }
    
    public static void displayList(ListNode first)
    {
        System.out.print("List(first-->last):");
        ListNode current = first;
        while (current != null)
        {
            System.out.print(current.data + " ");
            current = current.next;
        }
    }
    
    public static ListNode merageTwoLists(ListNode L1,ListNode L2)
    {
        if(L1 == null)return L2;
        if(L2 == null)return L1;
        if(L1.data < L2.data) {
            L1.next = merageTwoLists(L1.next,L2);
            return L1;
        }else {
            L2.next = merageTwoLists(L1,L2.next);
            return L2;
        }
    }
    
    public static void main(String[] args)
    {
        ListNode L1 = new ListNode(1);
        ListNode xnode1 = new ListNode(4);
        ListNode xnode2 = new ListNode(5);
        ListNode xnode3 = new ListNode(8);
        ListNode xnode4 = new ListNode(9);
        
        L1.next = xnode1;
        xnode1.next = xnode2;
        xnode2.next = xnode3;
        xnode3.next = xnode4;
        displayList(L1);
        
        System.out.println();
        
        ListNode L2 = new ListNode(2);
        ListNode ynode1 = new ListNode(3);
        ListNode ynode2 = new ListNode(7);
        ListNode ynode3 = new ListNode(9);
        ListNode ynode4 = new ListNode(10);
        
        L2.next = ynode1;
        ynode1.next = ynode2;
        ynode2.next = ynode3;
        ynode3.next = ynode4;
        displayList(L2);
        
        System.out.println();
        
        displayList(merageTwoLists(L1,L2));;
    }
}