A12289 | Ayoub and Lost Array
时间限制1s
内存限制256MB
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题目描述
Ayoub had an array $a$ of integers of size $n$ and this array had two interesting properties:
- All the integers in the array were between $l$ and $r$ (inclusive).
- The sum of all the elements was divisible by $3$ .
Unfortunately, Ayoub has lost his array, but he remembers the size of the array $n$ and the numbers $l$ and $r$ , so he asked you to find the number of ways to restore the array.
Since the answer could be very large, print it modulo $10^9 + 7$ (i.e. the remainder when dividing by $10^9 + 7$ ). In case there are no satisfying arrays (Ayoub has a wrong memory), print $0$ .
- All the integers in the array were between $l$ and $r$ (inclusive).
- The sum of all the elements was divisible by $3$ .
Unfortunately, Ayoub has lost his array, but he remembers the size of the array $n$ and the numbers $l$ and $r$ , so he asked you to find the number of ways to restore the array.
Since the answer could be very large, print it modulo $10^9 + 7$ (i.e. the remainder when dividing by $10^9 + 7$ ). In case there are no satisfying arrays (Ayoub has a wrong memory), print $0$ .
输入格式
The first and only line contains three integers $n$ , $l$ and $r$ ( $1 \le n \le 2 \cdot 10^5 , 1 \le l \le r \le 10^9$ ) — the size of the lost array and the range of numbers in the array.
输出格式
Print the remainder when dividing by $10^9 + 7$ the number of ways to restore the array.
输入输出样例
输入 #1
2 1 3
输出 #1
3
输入 #2
3 2 2
输出 #2
1
输入 #3
9 9 99
输出 #3
711426616
In the first example, the possible arrays are : $[1,2], [2,1], [3, 3]$ .
In the second example, the only possible array is $[2, 2, 2]$ .
In the second example, the only possible array is $[2, 2, 2]$ .
C++ 编辑器
输入
输出
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评测结果:Accepted