CF1895F.Fancy Arrays

普及/提高-

通过率:0%

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题目描述

Let's call an array aa of nn non-negative integers fancy if the following conditions hold:

  • at least one from the numbers xx , x+1x + 1 , ..., x+k1x+k-1 appears in the array;
  • consecutive elements of the array differ by at most kk (i.e. aiai1k|a_i-a_{i-1}| \le k for each i[2,n]i \in [2, n] ).

You are given nn , xx and kk . Your task is to calculate the number of fancy arrays of length nn . Since the answer can be large, print it modulo 109+710^9+7 .

输入格式

The first line contains a single integer tt ( 1t501 \le t \le 50 ) — the number of test cases.

The only line of each test case contains three integers nn , xx and kk ( 1n,k1091 \le n, k \le 10^9 ; 0x400 \le x \le 40 ).

输出格式

For each test case, print a single integer — the number of fancy arrays of length nn , taken modulo 109+710^9+7 .

输入输出样例

  • 输入#1

    4
    3 0 1
    1 4 25
    4 7 2
    1000000000 40 1000000000

    输出#1

    9
    25
    582
    514035484

说明/提示

In the first test case of the example, the following arrays are fancy:

  • [0,0,0][0, 0, 0] ;
  • [0,0,1][0, 0, 1] ;
  • [0,1,0][0, 1, 0] ;
  • [0,1,1][0, 1, 1] ;
  • [0,1,2][0, 1, 2] ;
  • [1,0,0][1, 0, 0] ;
  • [1,0,1][1, 0, 1] ;
  • [1,1,0][1, 1, 0] ;
  • [2,1,0][2, 1, 0] .
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