P21909 [HackerRank] Dortmund dilemma
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题目描述

Borussia Dortmund are a famous football ( soccer ) club from Germany. Apart from their fast-paced style of playing, the thing that makes them unique is the hard to pronounce names of their players ( błaszczykowski , papastathopoulos , großkreutz etc. ).

The team's coach is your friend. He is in a dilemma as he can't decide how to make it easier to call the players by name, during practice sessions. So, you advise him to assign easy names to his players. A name is easy to him if

  1. It consists of only one word.

  2. It consists of only lowercase english letters.

  3. Its length is exactly $N$.

  4. It contains exactly $\mbox{K}$ different letters from the $26$ letters of English alphabet.

  5. At least one of its proper prefixes matches with its proper suffix of same length.

Given, $N$ and $\mbox{K}$ you have to tell him the number of easy names he can choose from modulo $(10^9+9)$.

Note : A prefix $\mbox{P}$ of a name $\mbox{w}$ is proper if, $P\neq W$. Similarly, a suffix $\mbox{S}$ of a name $\mbox{W}$ is proper if, $S\neq W$.

Input Format

The first line of the input will contain $\mathbf{T}$ ( the number of testcases ).
Each of the next $\mathbf{T}$ lines will contain $2$ space separated integers $N$ and $\mbox{K}$.

Output Format

For each testcase, output the number of ways the coach can assign names to his players modulo $(10^9+9)$.

Constraints

$1\leq T\leq10^5$

$1\leq N\leq10^5$

$1\leq K\leq26$

Sample Input #1

3
1 1
2 1
4 2

Sample Output #1

0
26
2600

Sample Input #2

5
2 2
5 1
3 2
6 2
1 3

Sample Output #2

0
26
650
13650
0

输入格式

见题面

输出格式

见题面

样例输入
3 1 1 2 1 4 2
样例输出
0 26 2600