奇偶鏈表

一開始老是想着交換節點的值，但是這特麼是鏈表又不是數組，直接把奇數位的節點拿出來拼成一條鏈，偶數位也拼成一條鏈，然後將後者拼接到前者末尾，搞定。。。。。。。。。。

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode oddEvenList(ListNode head) {
        if (head == null || head.next == null){
            return head;
        }
        
        ListNode p1 = head;
        ListNode p2 = head.next;

        ListNode temp1 = p1;
        ListNode temp2 = p2;
        int count = 1;
        ListNode temp3 = p2.next;
        ListNode temp4 = null;
        while (temp3 != null){
            temp4 = temp3.next;
            if (count % 2 != 0){
                temp1.next = temp3;
                temp1 = temp1.next;
            }else {
                temp2.next = temp3;
                temp2 = temp2.next;
            }
            temp3.next = null;
            temp3 = temp4;
            count++;
        }
        temp2.next = null;
        temp1.next = p2;
        return p1;
    }
}