1package main 2 3type Node struct { 4 Circular bool 5} 6 7type ExtNode[V any] struct { 8 v V 9 Node 10} 11 12type List[V any] struct { 13 root *ExtNode[V] 14 len int 15} 16 17func (list *List[V]) PushBack(arg V) { 18 if list.len == 0 { 19 list.root = &ExtNode[V]{v: arg} 20 list.root.Circular = true 21 list.len++ 22 return 23 } 24 list.len++ 25} 26 27func main() { 28 var v List[int] 29 v.PushBack(1) 30} 31