Problem 6

通常第6题会比较难，今年的不一样？试着解，不对的话请指正。

There are n! different ways to arrange the jumps.
Given a point p between 0 and s = a_1+a_2+...a_n, it
has at most (n-1)! ways to reach. So the total ways to be matched is (n-1)(n-1)! which is less than n!. Also it
means there is at least one way that the grasshopper never lands on any point in M.

所有跟帖： 

• 通常第六题不是最难的 -累死算了- ♂ (148 bytes) () 07/26/2009 postreply 01:05:48

• 通常第六题是最难的 -botong- ♂ (408 bytes) () 07/26/2009 postreply 09:25:21

• 有点问题吧 -dynamic- ♂ (226 bytes) () 07/26/2009 postreply 22:14:34

• 回复：有点问题吧 -botong- ♂ (209 bytes) () 07/27/2009 postreply 11:01:10

• 回复：回复：有点问题吧 -dynamic- ♂ (79 bytes) () 07/27/2009 postreply 18:12:36

• 回复：回复：回复：有点问题吧 -botong- ♂ (91 bytes) () 07/28/2009 postreply 10:22:54