Max Sum Array

题意翻译

- 给定一个长为 $m$ 的序列 $c_1,c_2,\dots,c_m$。 - 序列 $A$ 满足：对于所有 $1 \leq i \leq m$，$i$ 在 $A$ 中出现了 $c_i$ 次。 - 定义一个序列 $A$ 的值如下： $$f(A)=\sum_{1 \leq i<j \leq n,a_i=a_j}j-i$$ - 求满足条件的 $f(A)$ 的最大值，及在取最大值时有多少种序列 $A$。 - $1 \leq m \leq 5 \times 10^5,1 \leq c_i \leq 10^6$。

题目描述

You are given an array $ c = [c_1, c_2, \dots, c_m] $ . An array $ a = [a_1, a_2, \dots, a_n] $ is constructed in such a way that it consists of integers $ 1, 2, \dots, m $ , and for each $ i \in [1,m] $ , there are exactly $ c_i $ occurrences of integer $ i $ in $ a $ . So, the number of elements in $ a $ is exactly $ \sum\limits_{i=1}^{m} c_i $ . Let's define for such array $ a $ the value $ f(a) $ as $ $f(a) = \sum_{\substack{1 \le i < j \le n\\ a_i = a_j}}{j - i}. $ $ </p><p>In other words, $ f(a) $ is the total sum of distances between all pairs of equal elements.</p><p>Your task is to calculate the maximum possible value of $ f(a) $ and the number of arrays yielding the maximum possible value of $ f(a)$. Two arrays are considered different, if elements at some position differ.

输入输出格式

输入格式

The first line contains a single integer $ m $ ( $ 1 \le m \le 5 \cdot 10^5 $ ) — the size of the array $ c $ . The second line contains $ m $ integers $ c_1, c_2, \dots, c_m $ ( $ 1 \le c_i \le 10^6 $ ) — the array $ c $ .

输出格式

Print two integers — the maximum possible value of $ f(a) $ and the number of arrays $ a $ with such value. Since both answers may be too large, print them modulo $ 10^9 + 7 $ .

输入输出样例

输入样例 #1

6
1 1 1 1 1 1

输出样例 #1

0 720

输入样例 #2

1
1000000

输出样例 #2

499833345 1

输入样例 #3

7
123 451 234 512 345 123 451

输出样例 #3

339854850 882811119

说明

In the first example, all possible arrays $ a $ are permutations of $ [1, 2, 3, 4, 5, 6] $ . Since each array $ a $ will have $ f(a) = 0 $ , so maximum value is $ f(a) = 0 $ and there are $ 6! = 720 $ such arrays. In the second example, the only possible array consists of $ 10^6 $ ones and its $ f(a) = \sum\limits_{1 \le i < j \le 10^6}{j - i} = 166\,666\,666\,666\,500\,000 $ and $ 166\,666\,666\,666\,500\,000 \bmod{10^9 + 7} = 499\,833\,345 $ .

题意翻译

- 给定一个长为 $m$ 的序列 $c_1,c_2,\dots,c_m$。 - 序列 $A$ 满足：对于所有 $1 \leq i \leq m$，$i$ 在 $A$ 中出现了 $c_i$ 次。 - 定义一个序列 $A$ 的值如下： $$f(A)=\sum_{1 \leq i<j \leq n,a_i=a_j}j-i$$ - 求满足条件的 $f(A)$ 的最大值，及在取最大值时有多少种序列 $A$。 - $1 \leq m \leq 5 \times 10^5,1 \leq c_i \leq 10^6$。