使用Python实现树的遍历算法和类型的树的遍历

class Node:
   def __init__(self,item):
        self.left=None
        self.right=None
        self.val=item
#中序遍历
def inorder(root):
   if root:
        inorder(root.left)
        print(str(root.val)+"->",end='')
        inorder(root.right)
#前序遍历
def postorder(root):
   if root:
        postorder(root.left)
        postorder(root.right)
        print(str(root.val)+"->",end='')
#后序遍历
def preorder(root):
   if root:
        print(str(root.val)+"->",end='')
        preorder(root.left)
        preorder(root.right)
root=Node(1)
root.left=Node(2)
root.right=Node(3)
root.left.left=Node(4)
root.left.right=Node(5)
print("中序遍历")
inorder(root)
print("前序遍历")
preorder(root)
print("后序遍历")
postorder(root)