#1003. 冒泡排序计数

冒泡排序计数

说明

算法提高&nbsp 冒泡排序计数&nbsp  
时间限制:1.0s&nbsp  &nbsp 内存限制:256.0MB
 &nbsp  &nbsp
  考虑冒泡排序的一种实现。
  bubble-sort&nbsp (A[],&nbsp n)
  > &nbsp round&nbsp =&nbsp 0
  > &nbsp while&nbsp A&nbsp is&nbsp not&nbsp sorted
  > &nbsp > &nbsp round&nbsp :=&nbsp round&nbsp +&nbsp 1
  > &nbsp > &nbsp for&nbsp i&nbsp :=&nbsp 1&nbsp to&nbsp n&nbsp -&nbsp 1
  > &nbsp > &nbsp > &nbsp if&nbsp (A[i]&nbsp > &nbsp A[i&nbsp +&nbsp 1])
  > &nbsp > &nbsp > &nbsp > &nbsp swap(A[i],&nbsp A[i&nbsp +&nbsp 1])
  求1&nbsp ..&nbsp n的排列中,有多少个排列使得A被扫描了K遍,亦即算法结束时round&nbsp ==&nbsp K。

  答案模20100713输出。
输入格式
  输入包含多组数据。每组数据为一行两个整数N,K。
输出格式
  对每组数据,输出一行一个整数表示答案。
样例输入
3
3&nbsp 0
3&nbsp 1
3&nbsp 2
样例输出
1
3
2
数据规模和约定
  T&nbsp < =&nbsp 10&nbsp ^&nbsp 5。
  1&nbsp < =&nbsp K&nbsp < &nbsp N&nbsp < &nbsp 10&nbsp ^&nbsp 6。