计算树中叶节点数的 Python 程序
当需要计算树中叶节点的数量时，会创建一个“Tree_structure”类，定义添加根值和其他子值的方法。给出了用户可以选择的各种选项。根据用户的选择，对Tree元素进行操作。
以下是相同的演示-
示例
class Tree_structure:
def __init__(self, data=None):
self.key= data
self.children= []
def set_root_node(self, data):
self.key= data
def add_vals(self, node):
self.children.append(node)
def search_val(self, key):
ifself.key== key:
return self
for child in self.children:
temp = child.search(key)
if temp is not None:
return temp
return None
def count_leaf_node(self):
leaf_nodes = []
self.count_leaf_node_helper_fun(leaf_nodes)
return len(leaf_nodes)
def count_leaf_node_helper_fun(self, leaf_nodes):
ifself.children== []:
leaf_nodes.append(self)
else:
for child in self.children:
child.count_leaf_node_helper_fun(leaf_nodes)
tree = None
print('Menu (this assumes no duplicate keys)')
print('add at root')
print('add below ')
print('count')
print('quit')
while True:
my_input = input('What operation would you like to perform ? ').split()
operation = my_input[0].strip().lower()
if operation == 'add':
data = int(my_input[1])
newNode = Tree_structure(data)
sub_op = my_input[2].strip().lower()
if sub_op == 'at':
tree = newNode
elif sub_op == 'below':
my_pos = my_input[3].strip().lower()
key = int(my_pos)
ref_node = None
if tree is not None:
ref_node = tree.search_val(key)
if ref_node is None:
print('No such key.')
continue
ref_node.add_vals(newNode)
elif operation == 'count':
if tree is None:
print('The tree is empty')
else:
count = tree.count_leaf_node()
print('The number of leaf nodes are : {}'.format(count))
elif operation == 'quit':
break输出结果Menu (this assumes no duplicate keys) add at root add below count quit What operation would you like to perform ? add 78 at root What operation would you like to perform ? add 90 below 78 What operation would you like to perform ? add 8 below 78 What operation would you like to perform ? count The number of leaf nodes are : 2 What operation would you like to perform ? quit
解释
'Tree_structure'类被创建。
它将“键”设置为True并将一个空列表设置为树的子项。
它有一个“set_root”函数，可以帮助设置树的根值。
定义了一个名为“add_vals”的方法，它有助于将元素添加到树中。
定义了另一个名为“search_val”的方法，它有助于搜索树中的元素。
定义了另一个名为“count_leaf_nodes”的方法，它有助于获取树的叶节点数。
定义了另一个名为“count_leaf_nodes_helper”的方法，它调用先前定义的函数——这是一个递归函数。
给出了四个选项，例如“在根目录添加”、“在下面添加”、“计数”和“退出”。
根据用户给出的选项，执行相应的操作。
此输出显示在控制台上。