二叉树构建

class TreeNode:
    def __init__(self, value=0, left=None, right=None):
        self.value = value
        self.left = left
        self.right = right

def build_binary_tree(values):
    if not values:
        return None
    
    root = TreeNode(values[0])
    queue = [root]
    index = 1
    
    while queue and index < len(values):
        node = queue.pop(0)
        
        if values[index] is not None:
            node.left = TreeNode(values[index])
            queue.append(node.left)
        index += 1
        
        if index < len(values) and values[index] is not None:
            node.right = TreeNode(values[index])
            queue.append(node.right)
        index += 1
    
    return root

# 示例用法
values = [1, 2, 3, None, 4, 5, 6]
root = build_binary_tree(values)