一道acm题,

一道acm题,
Problem H:Groups (I)
Time Limit:1000MS Memory Limit:65536K
Total Submit:93 Accepted:31
Description
　　There are n people in the class and
person pi has his value vi.Now,we'd like to put them into different groups.In
each group,there must be two people,and the value of this group is equal to
the minimum of two member's values.For example,if pi and pj are in the same
group,the value of their group is min(pi,pj).Now,your task is to tell the
maximum and minimum of the sum of all groups.
Input
　　There are several test cases.
　　In
each case,there is an even integer n(n