Count binary strings
Submissions: 467   Accuracy:

27.14%

  Difficulty: Easy   Marks: 2

Given two integers n and k, count the number of binary strings of length n with k as number of times adjacent 1’s appear.

Input:
The first line of input contains an integer T denoting the number of test cases. Then T test cases follow. The first line of each test case contains the two integers N and K.

Output:
Print the answer for each testcase in a new line. Since the answer can be quiet large output the answer modulo 109+7.

Constraints:
1<=T <=100
1<= N, K <=1000

Example:
Input:
1
5 2

Output:
6

** For More Input/Output Examples Use 'Expected Output' option **

Contributor: Sujnesh Mishra
Author: sujnesh


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