Golang Leetcode 876. Middle of the Linked List.go

type ListNode struct {
	Val  int
	Next *ListNode
}
func middleNode(head *ListNode) *ListNode {
	if head == nil || head.Next == nil {
		return head
	}
	fast := head
	slow := head
	for fast != nil {
		if fast.Next == nil {
			break
		}
		fast = fast.Next
		slow = slow.Next
		if fast.Next != nil {
			fast = fast.Next
		}
	}
	return slow
}