class TreeToSequence:
def toSequence(self, root):
if not root:#该树为空,则返回的字符串也为空
return ''
left,right=root.left,root.right
if left==None and right==None:#左右子树皆为空,则只有该数本身的括号
return '()'
else:
return '('+self.toSequence(left)+self.toSequence(right)+')'
class TreeToSequence:
def toSequence(self, root):
if not root: return ""
res = "("
res += self.toSequence(root.left)
res += self.toSequence(root.right)
res += ")"
return res