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.

public class Solution{public ListNode mergeTwoLists(ListNode l1, ListNode l2){ListNode start;if (l1 == null)return l2;if (l2 == null)return l1;//对输入进行最简单的判断，这已经是一个必须的步骤了~if (l1.val < l2.val){start = l1;start.next = mergeTwoLists(l1.next, l2);} else {start = l2;start.next = mergeTwoLists(l1, l2.next);}//对数据判断然后递归~return start;}}

又是一道水题~