1186. Anniversary party

单点时限: 2.0 sec

内存限制: 256 MB

There is going to be a party to celebrate the 80-th Anniversary of the Ural State University. The University has a hierarchical structure of employees. It means that the supervisor relation forms a tree rooted at the rector V. E. Tretyakov. In order to make the party funny for every one, the rector does not want both an employee and his or her immediate supervisor to be present. The personnel office has evaluated conviviality of each employee, so everyone has some number (rating) attached to him or her. Your task is to make a list of guests with the maximal possible sum of guests’ conviviality ratings.

输入格式

Employees are numbered from 1 to N. A first line of input contains a number N. 1 <= N <= 6 000. Each of the subsequent N lines contains the conviviality rating of the corresponding employee. Conviviality rating is an integer number in a range from -128 to 127. After that go N – 1 lines that describe a supervisor relation tree. Each line of the tree specification has the form:

L K

It means that the K-th employee is an immediate supervisor of the L-th employee. Input is ended with the line

0 0

输出格式

Output should contain the maximal sum of guests’ ratings.

样例

Input
7
1
1
1
1
1
1
1
1 3
2 3
6 4
7 4
4 5
3 5
0 0
Output
5

21 人解决,23 人已尝试。

32 份提交通过,共有 47 份提交。

3.4 EMB 奖励。

创建: 12 年,8 月前.

修改: 2 年,5 月前.

最后提交: 9 月,1 周前.

来源: sunny_fable

题目标签
DP