#P1167F. Scalar Queries

    ID: 1971 远端评测题 2000ms 256MiB 尝试: 4 已通过: 1 难度: 8 上传者: 标签>combinatoricsdata structuresmathsortings*2300

Scalar Queries

Description

You are given an array $a_1, a_2, \dots, a_n$. All $a_i$ are pairwise distinct.

Let's define function $f(l, r)$ as follows:

  • let's define array $b_1, b_2, \dots, b_{r - l + 1}$, where $b_i = a_{l - 1 + i}$;
  • sort array $b$ in increasing order;
  • result of the function $f(l, r)$ is $\sum\limits_{i = 1}^{r - l + 1}{b_i \cdot i}$.

Calculate $\left(\sum\limits_{1 \le l \le r \le n}{f(l, r)}\right) \mod (10^9+7)$, i.e. total sum of $f$ for all subsegments of $a$ modulo $10^9+7$.

The first line contains one integer $n$ ($1 \le n \le 5 \cdot 10^5$) — the length of array $a$.

The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($1 \le a_i \le 10^9$, $a_i \neq a_j$ for $i \neq j$) — array $a$.

Print one integer — the total sum of $f$ for all subsegments of $a$ modulo $10^9+7$

Input

The first line contains one integer $n$ ($1 \le n \le 5 \cdot 10^5$) — the length of array $a$.

The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($1 \le a_i \le 10^9$, $a_i \neq a_j$ for $i \neq j$) — array $a$.

Output

Print one integer — the total sum of $f$ for all subsegments of $a$ modulo $10^9+7$

Samples

4
5 2 4 7
167
3
123456789 214365879 987654321
582491518

Note

Description of the first example:

  • $f(1, 1) = 5 \cdot 1 = 5$;
  • $f(1, 2) = 2 \cdot 1 + 5 \cdot 2 = 12$;
  • $f(1, 3) = 2 \cdot 1 + 4 \cdot 2 + 5 \cdot 3 = 25$;
  • $f(1, 4) = 2 \cdot 1 + 4 \cdot 2 + 5 \cdot 3 + 7 \cdot 4 = 53$;
  • $f(2, 2) = 2 \cdot 1 = 2$;
  • $f(2, 3) = 2 \cdot 1 + 4 \cdot 2 = 10$;
  • $f(2, 4) = 2 \cdot 1 + 4 \cdot 2 + 7 \cdot 3 = 31$;
  • $f(3, 3) = 4 \cdot 1 = 4$;
  • $f(3, 4) = 4 \cdot 1 + 7 \cdot 2 = 18$;
  • $f(4, 4) = 7 \cdot 1 = 7$;