[LeetCode]--21. Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

这里sorted说的是从小到大。

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
   
   
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode ln = new ListNode(