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 node1 = new ListNode(-1);
        ListNode node2 = new ListNode(-1);

        ListNode node11 = node1;
        ListNode node22 = node2;
        ListNode head1 = head;

        int i = 1;
        while(head1 != null){
            if (i%2 ==0) {
                node22.next = head1;
                node22=node22.next;
            } else{
                node11.next = head1;
                node11=node11.next;
            }
            head1 = head1.next;
            i++;
        }
        node22.next = null;
        node11.next = node2.next;

        return node1.next;
    }
}