golang二叉树前序，中序，后序非递归遍历算法

package mainimport (   "container/list"   "fmt")// Binary Treetype BinaryTree struct {   Data  interface{}   Left  *BinaryTree   Right *BinaryTree}// Constructorfunc NewBinaryTree(data interface{}) *BinaryTree {   return &BinaryTree{Data: data}}// 先序遍历-非递归func (bt *BinaryTree) PreOrderNoRecursion() []interface{} {   t := bt   stack := list.New()   res := make([]interface{}, 0)   for t != nil || stack.Len() != 0 {      for t != nil {         res = append(res, t.Data)//visit         stack.PushBack(t)         t = t.Left      }      if stack.Len() != 0 {         v := stack.Back()         t = v.Value.(*BinaryTree)         t = t.Right         stack.Remove(v)      }   }   return res}// 中序遍历-非递归func (bt *BinaryTree) InOrderNoRecursion() []interface{} {   t := bt   stack := list.New()   res := make([]interface{}, 0)   for t != nil || stack.Len() != 0 {      for t != nil {         stack.PushBack(t)         t = t.Left      }      if stack.Len() != 0 {         v := stack.Back()         t = v.Value.(*BinaryTree)         res = append(res, t.Data)//visit         t = t.Right         stack.Remove(v)      }   }   return res}// 后序遍历-非递归func (bt *BinaryTree) PostOrderNoRecursion() []interface{} {   t := bt   stack := list.New()   res := make([]interface{}, 0)   var preVisited *BinaryTree   for t != nil || stack.Len() != 0 {      for t != nil {         stack.PushBack(t)         t = t.Left      }      v   := stack.Back()      top := v.Value.(*BinaryTree)      if (top.Left == nil && top.Right == nil) || (top.Right == nil && preVisited == top.Left) || preVisited == top.Right{         res = append(res, top.Data)//visit         preVisited = top         stack.Remove(v)      }else {         t = top.Right      }   }   return res}func main() {   t := NewBinaryTree(1)   t.Left  = NewBinaryTree(3)   t.Right = NewBinaryTree(6)   t.Left.Left = NewBinaryTree(4)   t.Left.Right = NewBinaryTree(5)   t.Left.Left.Left = NewBinaryTree(7)   fmt.Println(t.PreOrderNoRecursion())   fmt.Println(t.InOrderNoRecursion())   fmt.Println(t.PostOrderNoRecursion())}