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 {
    /**
     * 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
     *
     * 
     * @param head ListNode类 
     * @return ListNode类
     */
    public ListNode oddEvenList (ListNode head) {
        // write code here
        if(head == null || head.next == null){
            return head;
        }
        Queue<ListNode> queue1 = new LinkedList<ListNode>();
        Queue<ListNode> queue2 = new LinkedList<ListNode>();
        boolean flag = true;
        ListNode temp = null;
        while(head != null){
            if(flag){
                queue1.offer(head);
                flag = false;
            }else{
                queue2.offer(head);
                flag = true;
            }
            head = head.next;
        }
        
        flag = true;
        while(!queue1.isEmpty()){
            if(flag){
                head = queue1.poll();
                temp = head;
                flag = false;
                continue;
            }
            temp.next = queue1.poll();
            temp = temp.next;
        }
        while(!queue2.isEmpty()){
            temp.next = queue2.poll();
            temp = temp.next;
        }
        temp.next = null;
        return head;
    }
}