📅  最后修改于: 2022-03-11 14:45:52.446000             🧑  作者: Mango
def to_string(node):
def actual_recursive(node):
nonlocal a_str # ~global, can modify surrounding function's scope.
a_str += str(node.val)
if node.next != None:
actual_recursive(node.next)
a_str = ''
actual_recursive(node)
return a_str