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) {
        if(head==null){
          return head;
        }
        // write code here
        ListNode m = head;
        ListNode p = head.next;
        ListNode n = head.next;
        while (n != null && n.next != null) {
            m.next = n.next;
            m = n.next;
            n.next = m.next;
            n = m.next;
        }
        m.next = p;
        return head;
    }
}