写一段代码实现完全二叉树

Sure, here is an example code to implement a complete binary tree in Python:

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

class CompleteBinaryTree:
    def __init__(self):
        self.root = None
    
    def insert(self, val):
        new_node = Node(val)
        if self.root is None:
            self.root = new_node
            return
        queue = [self.root]
        while queue:
            curr = queue.pop(0)
            if curr.left is None:
                curr.left = new_node
                break
            elif curr.right is None:
                curr.right = new_node
                break
            queue.append(curr.left)
            queue.append(curr.right)

This code defines a `Node` class for each node in the tree and a `CompleteBinaryTree` class to represent the entire tree. The `insert` method adds a new node to the tree by traversing the tree in a breadth-first manner and finding the first empty spot for the new node. This ensures that the tree remains complete.