如何创建特定的二叉树？

# 定义二叉树节点
class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

# 创建完全二叉树
def createCompleteBinaryTree(nums):
    if not nums:
        return None
    
    nodes = [TreeNode(num) for num in nums]
    for i in range(len(nums) // 2):
        if 2 * i + 1 < len(nums):
            nodes[i].left = nodes[2 * i + 1]
        if 2 * i + 2 < len(nums):
            nodes[i].right = nodes[2 * i + 2]
    
    return nodes[0]

# 测试创建完全二叉树
nums = [1, 2, 3, 4, 5, 6, 7]
root = createCompleteBinaryTree(nums)