给定一棵树，最简单的方法是计算给定节点上所有子代的总和？
说一棵这样的树...
红色值表示节点及其子节点的总和。
假设节点结构看起来像这样（一个示例）：
class Node:
def __init__(self, name):
self.children = []
self.weight = 100
self.weight_plus_children = 295
如何以有效的单遍方式（在Python中）执行此操作？
谢谢！
最佳答案
只需判断节点是否为叶子并将其总和添加到权重即可，这是一个示例：
class Node:
def __init__(self, name, weight, children):
self.children = children
self.weight = weight
self.weight_plus_children = weight
def get_all_weight(self):
if self.children is None:
return self.weight_plus_children
else:
for child in self.children:
print "child.get_all_weight()", child.get_weigth_with_children()
self.weight_plus_children += child.get_weigth_with_children()
return self.weight_plus_children
def get_weigth_with_children(self):
return self.weight_plus_children
leaf1 = Node('C1', 58, None)
leaf2 = Node('C2', 7, None)
leaf3 = Node('C3', 10, None)
leaf4 = Node('C4', 20, None)
subroot = Node('B1', 50, [leaf1, leaf2])
subroot1 = Node('B2', 50, [leaf3, leaf4])
root = Node('A', 100, [subroot, subroot1])
print subroot.get_all_weight()
print
print subroot1.get_all_weight()
print
print root.get_all_weight()
输出：
F:\so>python test-tree.py
child.get_all_weight() 58
child.get_all_weight() 7
115
child.get_all_weight() 10
child.get_all_weight() 20
80
child.get_all_weight() 115
child.get_all_weight() 80
295