876. 链表的中间结点

题目如下：

https://leetcode.cn/problems/middle-of-the-linked-list/description/

Java代码如下：

`
class ListNode {
int val;
ListNode next;
ListNode() {}
ListNode(int val) { this.val = val; }
ListNode(int val, ListNode next) { this.val = val; this.next = next; }
}
class Solution {
public static void main(String[] args) {

}
public static ListNode middleNode(ListNode head) {
    ListNode h1=head,h2=h1;
    while (h2.next!=null&&h2.next.next!=null){
        h1=h1.next;
        h2=h2.next.next;
    }
    if (h2.next!=null){
        return h1.next;
    }
    return h1;
}

}
`