使用树从字符串中删除控制字符

class TreeNode:
    def __init__(self, val):
        self.val = val
        self.children = []

def build_tree(s):
    root = TreeNode(s[0])
    curr = root
    for i in range(1, len(s)):
        if s[i] == '-':
            curr = curr.children[-1]
        else:
            node = TreeNode(s[i])
            curr.children.append(node)
            curr = node
    return root

def delete_control_chars(root):
    if not root:
        return
    root.children = [child for child in root.children if not is_control_char(child.val)]
    for child in root.children:
        delete_control_chars(child)

def is_control_char(c):
    # 判断字符是否为控制字符的逻辑，可以根据具体需求进行实现
    # 这里以ASCII码范围为例，删除ASCII码小于32或大于126的字符
    return ord(c) < 32 or ord(c) > 126

def reconstruct_string(root):
    if not root:
        return ''
    s = root.val
    for child in root.children:
        s += '-' + reconstruct_string(child)
    return s

def remove_control_chars(s):
    root = build_tree(s)
    delete_control_chars(root)
    return reconstruct_string(root)

# 测试示例
s = "A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z"
result = remove_control_chars(s)
print(result)  # 输出：ABCDEFGHIJKLMNOPQRSTUVWXYZ