题解 | #链表的奇偶重排#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    public ListNode oddEvenList (ListNode head) {
        if(head==null||head.next==null){
            return head;
        }
        ListNode n1=head;
        ListNode pre1=n1;
        ListNode n2=head.next;
        ListNode pre2=n2;
        head=head.next.next;
        while(head!=null&&head.next!=null){
            n1.next=head;
            n1=n1.next;
            n2.next=head.next;
            n2=n2.next;
            head=head.next.next;
        }
        if(head!=null){
            n1.next=head;
            n1=n1.next;
        }
        n1.next=pre2;
        n2.next=null;
        return pre1;
    }
}