（链表）14-链表的奇偶重排

 1 import java.util.*;
 2 
 3 /*
 4  * public class ListNode {
 5  *   int val;
 6  *   ListNode next = null;
 7  *   public ListNode(int val) {
 8  *     this.val = val;
 9  *   }
10  * }
11  */
12 public class Solution {
13     /**
14      * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
15      * @param head ListNode类
16      * @return ListNode类
17      */
18     public ListNode oddEvenList (ListNode head) {
19         // 判空链表
20         if (head == null) {
21             return head;
22         }
23         // 奇数链表的指针
24         ListNode one = head;
25         // 偶数链表的指针
26         ListNode two = head.next;
27         // 临时指针记录偶数链表的头指针-用于最后奇偶相连
28         ListNode temp = two;
29         while (two != null && two.next != null) {
30             one.next = two.next;
31             one = two.next;
32             two.next = one.next;
33             two = one.next;
34         }
35         // 奇偶链表相连
36         one.next = temp;
37         // 返回结果
38         return head;
39     }
40 }