Problem F. Period Sequence
时间限制 6000 ms
内存限制 63.9990234375 MB
Chiaki has $n$ integers $s_0,s_1,\dots,s_{n-1}$. She has defined an infinite sequence $S$ in the following way: $S_k = s_{k \bmod n} + n \cdot \lfloor \frac{k}{n} \rfloor$, where $k$ is a zero based index.
For a continuous subsequence $S[l..r]$, let $cnt_x$ be the number of occurrence of $x$ in the subsequence $S[l..r]$. Then the value of $S[l..r]$ is defined as follows $$f(l,r)=\sum\limits_{x}x \cdot cnt^2_x$$
For two integers $a$ and $b$ ($a \le b$), Chiaki would like to find the value of $$(\sum\limits_{a \le l \le r \le b} f(l,r)) \bmod (10^9+7)$$
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输出数据
For each test case, output an integer denoting the answer.
样例输入
复制
4
3 2 6
2 1 3
5 2 7
2 1 5 1 2
4 4 8
2 1 5 17
3 5 9
2 5 2
样例输出
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