题解 | #链表的奇偶重排#

package main
import . "nc_tools"
/*
 * type ListNode struct{
 *   Val int
 *   Next *ListNode
 * }
 */

/**
 * 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
*/
func oddEvenList(head *ListNode) *ListNode {
	// write code here
    if head==nil{
        return nil
    }
	var odd, even, even_head *ListNode //双指针，隔一步。奇数为时后数位的下一步，偶数位是奇数位的下一步，不用考虑为空，会赋值空
	odd = head
	even = head.Next
	even_head = head.Next
	for even != nil && even.Next != nil {
		odd.Next = even.Next
		odd = even.Next
		even.Next = odd.Next
		even = odd.Next
	}
	odd.Next = even_head
	return head
}