Preparando MOJI
Let's call beauty of an array $$$b_1, b_2, \ldots, b_n$$$ ($$$n > 1$$$) — $$$\min\limits_{1 \leq i < j \leq n} |b_i - b_j|$$$.
You're given an array $$$a_1, a_2, \ldots a_n$$$ and a number $$$k$$$. Calculate the sum of beauty over all subsequences of the array of length exactly $$$k$$$. As this number can be very large, output it modulo $$$998244353$$$.
A sequence $$$a$$$ is a subsequence of an array $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero or all) elements.
The first line contains integers $$$n, k$$$ ($$$2 \le k \le n \le 1000$$$).
The second line contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$0 \le a_i \le 10^5$$$).
Output one integer — the sum of beauty over all subsequences of the array of length exactly $$$k$$$. As this number can be very large, output it modulo $$$998244353$$$.
4 3 1 7 3 5
8
5 5 1 10 100 1000 10000
9
In the first example, there are $$$4$$$ subsequences of length $$$3$$$ — $$$[1, 7, 3]$$$, $$$[1, 3, 5]$$$, $$$[7, 3, 5]$$$, $$$[1, 7, 5]$$$, each of which has beauty $$$2$$$, so answer is $$$8$$$.
In the second example, there is only one subsequence of length $$$5$$$ — the whole array, which has the beauty equal to $$$|10-1| = 9$$$.
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Provedor Codeforces
Código CF1188C
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Datas 09/05/2023 09:49:37
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