1909：Marbles on a tree

题目描述

n boxes are placed on the vertices of a rooted tree, which are numbered from 1 to n, 1 <= n <= 10000. Each box is either empty or contains a number of marbles; the total number of marbles is n.
The task is to move the marbles such that each box contains exactly one marble. This is to be accomplished be a sequence of moves; each move consists of moving one marble to a box at an adjacent vertex. What is the minimum number of moves required to achieve the goal?

输入解释

The input contains a number of cases. Each case starts with the number n followed by n lines. Each line contains at least three numbers which are: v the number of a vertex, followed by the number of marbles originally placed at vertex v followed by a number d which is the number of children of v, followed by d numbers giving the identities of the children of v.
The input is terminated by a case where n = 0 and this case should not be processed.

输出解释

For each case in the input, output the smallest number of moves of marbles resulting in one marble at each vertex of the tree.

输入样例

9
1 2 3 2 3 4
2 1 0
3 0 2 5 6
4 1 3 7 8 9
5 3 0
6 0 0
7 0 0
8 2 0
9 0 0
9
1 0 3 2 3 4
2 0 0
3 0 2 5 6
4 9 3 7 8 9
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
9
1 0 3 2 3 4
2 9 0
3 0 2 5 6
4 0 3 7 8 9
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
0

输出样例

7
14
20

该题目是Virtual Judge题目，来自北京大学POJ

题目来源 Waterloo local 2004.06.12

源链接： POJ-1909

最后修改于 2020-10-29T06:17:27+00:00 由爬虫自动更新

共提交 0 次

通过率 --%

时间上限	内存上限
1000	30000