A16330 | Fancy Arrays
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内存限制256MB
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题目描述
Let's call an array $a$ of $n$ non-negative integers fancy if the following conditions hold:
- at least one from the numbers $x$ , $x + 1$ , ..., $x+k-1$ appears in the array;
- consecutive elements of the array differ by at most $k$ (i.e. $|a_i-a_{i-1}| \le k$ for each $i \in [2, n]$ ).
You are given $n$ , $x$ and $k$ . Your task is to calculate the number of fancy arrays of length $n$ . Since the answer can be large, print it modulo $10^9+7$ .
- at least one from the numbers $x$ , $x + 1$ , ..., $x+k-1$ appears in the array;
- consecutive elements of the array differ by at most $k$ (i.e. $|a_i-a_{i-1}| \le k$ for each $i \in [2, n]$ ).
You are given $n$ , $x$ and $k$ . Your task is to calculate the number of fancy arrays of length $n$ . Since the answer can be large, print it modulo $10^9+7$ .
输入格式
The first line contains a single integer $t$ ( $1 \le t \le 50$ ) — the number of test cases.
The only line of each test case contains three integers $n$ , $x$ and $k$ ( $1 \le n, k \le 10^9$ ; $0 \le x \le 40$ ).
The only line of each test case contains three integers $n$ , $x$ and $k$ ( $1 \le n, k \le 10^9$ ; $0 \le x \le 40$ ).
输出格式
For each test case, print a single integer — the number of fancy arrays of length $n$ , taken modulo $10^9+7$ .
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
In the first test case of the example, the following arrays are fancy:
- $[0, 0, 0]$ ;
- $[0, 0, 1]$ ;
- $[0, 1, 0]$ ;
- $[0, 1, 1]$ ;
- $[0, 1, 2]$ ;
- $[1, 0, 0]$ ;
- $[1, 0, 1]$ ;
- $[1, 1, 0]$ ;
- $[2, 1, 0]$ .
- $[0, 0, 0]$ ;
- $[0, 0, 1]$ ;
- $[0, 1, 0]$ ;
- $[0, 1, 1]$ ;
- $[0, 1, 2]$ ;
- $[1, 0, 0]$ ;
- $[1, 0, 1]$ ;
- $[1, 1, 0]$ ;
- $[2, 1, 0]$ .
C++ 编辑器
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评测结果:Accepted