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
        ListNode cur = head;
        ListNode one = new ListNode(-1);
        ListNode two = new ListNode(-1);
        ListNode tail_1 = one;
        ListNode tail_2 = two;
        while(cur!=null){
            tail_1.next = cur;
            cur = cur.next;
            tail_1 = tail_1.next;
            if(cur!=null){
                tail_2.next = cur;
                cur = cur.next;
                tail_2 = tail_2.next;
            }
        }
        
        tail_1.next = two.next;
        tail_2.next = null;
        return one.next;
    }
}