2785. hear tree

单点时限: 2.0 sec

内存限制: 256 MB

If a tree falls in the forest, and there’s nobody there to hear, does it make a sound? This classic conundrum was coined by George Berkeley (1685-1753), the Bishop and influential Irish philosopher whose primary philosophical achievement is the advancement of what has come to be called subjective idealism. He wrote a number of works, of which the most widely-read are Treatise Concerning the Principles of Human Knowledge (1710) and Three Dialogues between Hylas and Philonous (1713) (Philonous, the “lover of the mind,” representing Berkeley himself).


In each testcase, a forest contains P people numbered from 1 to P and N trees numbered from 1 to N. Standard input consists of a line containing P and N and K followed by K lines, containing a pair of integers i and j, indicating that person i has heard tree j fall. People may have different opinions as to which trees, according to Berkeley, have made a sound. How many different opinions are represented in the input? Two people hold the same opinion only if they hear exactly the same set of trees. You may assume that P < 100 and N < 100.


Output one line,with the answer described above;


3 4 6
1 2
3 3
1 3
2 2
3 2
2 4

22 人解决,37 人已尝试。

28 份提交通过,共有 103 份提交。

5.5 EMB 奖励。

创建: 14 年,2 月前.

修改: 6 年,6 月前.

最后提交: 7 月,4 周前.

来源: ECNU 2009 ACM selective trial From waterloo