TypeDB Forces 2023 (Div. 1 + Div. 2, Rated, Prizes!)
C
Remove the Bracket
Codeforces
1600
原题
← BD →
翻译中…

RSJ has a sequence $a$ of $n$ integers $a_1,a_2, \ldots, a_n$ and an integer $s$. For each of $a_2,a_3, \ldots, a_{n-1}$, he chose a pair of non-negative integers $x_i$ and $y_i$ such that $x_i+y_i=a_i$ and $(x_i-s) \cdot (y_i-s) \geq 0$.

翻译中…

Now he is interested in the value $$F = a_1 \cdot x_2+y_2 \cdot x_3+y_3 \cdot x_4 + \ldots + y_{n - 2} \cdot x_{n-1}+y_{n-1} \cdot a_n.$$

翻译中…

Please help him find the minimum possible value $F$ he can get by choosing $x_i$ and $y_i$ optimally. It can be shown that there is always at least one valid way to choose them.

翻译中…

Input

翻译中…

Each test contains multiple test cases. The first line contains an integer $t$ ($1 \le t \le 10^4$) — the number of test cases.

翻译中…

The first line of each test case contains two integers $n$, $s$ ($3 \le n \le 2 \cdot 10^5$; $0 \le s \le 2 \cdot 10^5$).

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The second line contains $n$ integers $a_1,a_2,\ldots,a_n$ ($0 \le a_i \le 2 \cdot 10^5$).

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It is guaranteed that the sum of $n$ does not exceed $2 \cdot 10^5$.

翻译中…

Output

翻译中…

For each test case, print the minimum possible value of $F$.

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Note

翻译中…

In the first test case, $2\cdot 0+0\cdot 1+0\cdot 3+0\cdot 4 = 0$.

翻译中…

In the second test case, $5\cdot 1+2\cdot 2+2\cdot 2+1\cdot 5 = 18$.

翻译中…

样例

Input #1
10
5 0
2 0 1 3 4
5 1
5 3 4 3 5
7 2
7 6 5 4 3 2 1
5 1
1 2 3 4 5
5 2
1 2 3 4 5
4 0
0 1 1 1
5 5
4 3 5 6 4
4 1
0 2 1 0
3 99999
200000 200000 200000
6 8139
7976 129785 12984 78561 173685 15480
Output #1
0
18
32
11
14
0
16
0
40000000000
2700826806
InputCopy OutputCopy
题目信息
题号
1787C
时间限制
1 s
内存限制
256 MB
标签
动态规划
贪心
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。