题目链接

题意：问长度为n，每个位置由且仅有‘H’和’T’组成的序列中，至少有连续k个‘H’出现的方案数。

思路：不会做，参考了题解 不过没有完全搞懂。

1655: [Usaco2006 Jan] Dollar Dayz 奶牛商店

Time Limit: 5 Sec  Memory Limit: 64 MB Submit: 353  Solved: 190 [Submit][Status][Discuss]

Description

Farmer John goes to Dollar Days at The Cow Store and discovers an unlimited number of tools on sale. During his first visit, the tools are selling variously for $1, $2, and $3. …