当前你的浏览器版本过低,网站已在兼容模式下运行,兼容模式仅提供最小功能支持,网站样式可能显示不正常。
请尽快升级浏览器以体验网站在线编辑、在线运行等功能。

建议使用的浏览器:

谷歌Chrome 火狐Firefox Opera浏览器 微软Edge浏览器 QQ浏览器 360浏览器 傲游浏览器

2781:The mysterious X network

题目描述
One of the reasons for which École polytechnique (nicknamed ``X" for reasons to be explained during the debriefing talk) is so deeply rooted in French society is its famous network of camarades - former students of the same school. When one camarade wants something (money, job, etc.), he can ask this network for help and support. In practice, this means that when he/she wants to reach some other camarade, not always of the same year, then surely he can find intermediate camarades to get to her/him. Note that the ``camarade" relationship is symmetric. Due to the magic of the X network, there is always a means to reach anybody.

The program you have to write is supposed to help to minimize the number of these intermediate camarades.
输入解释
The huge file of all living camarades is simplified so as to obey the following format. The first line in the file is the number of camarades, say N , an integer 1<=N<=105 . Camarades are labeled from 0 to N - 1 . Follow N lines. Each line starts with the camarade label c , followed by the number of other camarades he/she knows, say nc , followed by the labels of those nc camarades. All these integers are separated by a single blank. It is assumed that nc is always less than 100. The last line in the file is the label of the camarade seeking help (say c1 ) followed by the label of the camarade he wants help from, say c2 ( c2 != c1 ).
输出解释
Your program should output three integers separated by a blank: c1 , c2 and the minimal number of intermediate camarades to reach c2 .
输入样例
4
0 3 1 2 3
1 1 0
2 2 0 3
3 2 0 2
1 2
输出样例
1 2 1

该题目是Virtual Judge题目,来自 北京大学POJ

源链接: POJ-2781

最后修改于 2020-10-29T06:43:25+00:00 由爬虫自动更新

共提交 0

通过率 --%
时间上限 内存上限
10000 228000