LeetCode--021--合并两个有序链表(java)

时间:2022-04-26 19:01:44

将两个有序链表合并为一个新的有序链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。

示例:

输入:1->2->4, 1->3->4
输出:1->1->2->3->4->4

哎,这java语法忘完了,也能糊弄通过,老天真要我搞大数据开发吗???????AI我还能刚多久。。。。。。。。。。

 /**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
ListNode l3 = new ListNode(-1);
ListNode dummy = l3;
while(l1!=null && l2 != null){
if(l1.val < l2.val){
dummy.next = l1;
dummy = l1;
l1 = l1.next;
}else{
dummy.next = l2;
dummy = l2;
l2 = l2.next;
}
}
if(l1 == null){
l1 = l2;
}
dummy.next = l1;
return l3.next;
}
}

官方的递归:

 class Solution {
public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
if(l1 == null) return l2;
if(l2 == null) return l1;
if(l1.val < l2.val){
l1.next = mergeTwoLists(l1.next,l2);
return l1;
}else{
l2.next = mergeTwoLists(l1,l2.next);
return l2;
}
}
}

2019-04-18 20:54:58