已知如下一棵二叉树对应的字符序列（层次遍历序列）为：ABC##EF#G####，其中‘#’表示节点对应的孩子结点为空。现给定一棵二叉树的字符序列，请使用二叉链表构造该二叉树，并输出该二叉树的中序遍历。

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

# 构造二叉树
def buildTree(s):
    if not s:
        return None
    root = TreeNode(s[0])
    queue = [root]
    i = 1
    while queue:
        node = queue.pop(0)
        if i < len(s) and s[i] != '#':
            node.left = TreeNode(s[i])
            queue.append(node.left)
        i += 1
        if i < len(s) and s[i] != '#':
            node.right = TreeNode(s[i])
            queue.append(node.right)
        i += 1
    return root

# 中序遍历二叉树
def inorderTraversal(root):
    if not root:
        return []
    res = []
    stack = []
    while root or stack:
        while root:
            stack.append(root)
            root = root.left
        root = stack.pop()
        res.append(root.val)
        root = root.right
    return res

# 构造二叉树并输出中序遍历
s = "ABC##EF#G####"
root = buildTree(s)
print(inorderTraversal(root))