class Node: def init(self,val): self.value=val self.left=None self.right=None

class Tree: def init(self): self.root=None

def insert(self,root,val):
    if root is None:
        return Node(val)
    elif root.value>val:
        root.left=self.insert(root.left,val)
    else:
        root.right=self.insert(root.right,val)

    return root

def preOrder(self,root):
    if root is None:
        return 
    print(root.value,end=' ')
    self.preOrder(root.left)
    self.preOrder(root.right)

n=int(input()) nums=list(map(int,input().split())) tree=Tree() tree.root=Node(nums[0]) for num in nums[1:]: tree.insert(tree.root,num) tree.preOrder(tree.root)

There is a gotcha here, that the C# template doesn't parse the input like the languages. And the description doesn't describe how to parse the input.

def preOrder(root): if(root==None): return 0 print(root.info, end=" ") preOrder(root.left) preOrder(root.right)

JAVA:

    public static void preOrder(Node node) {
        if (node != null) {
            System.out.print(node.data + " ");
            preOrder(node.left);
            preOrder(node.right);
        }
    }