题目描述
Tenzing has a beautiful necklace. The necklace consists of $n$ pearls numbered from $1$ to $n$ with a string connecting pearls $i$ and $(i \text{ mod } n)+1$ for all $1 \leq i \leq n$.
One day Tenzing wants to cut the necklace into several parts by cutting some strings. But for each connected part of the necklace, there should not be more than $k$ pearls. The time needed to cut each string may not be the same. Tenzing needs to spend $a_i$ minutes cutting the string between pearls $i$ and $(i \text{ mod } n)+1$.
Tenzing wants to know the minimum time in minutes to cut the necklace such that each connected part will not have more than $k$ pearls.
Input
Each test contains multiple test cases. The first line of input contains a single integer $t$ ($1 \le t \le 10^5$) — the number of test cases. The description of test cases follows.
The first line of each test case contains two integers $n$ and $k$ ($2\leq n\leq 5\cdot 10^5$, $1\leq k <n$).
The second line of each test case contains $n$ integers $a_1,a_2,\ldots,a_n$ ($1\leq a_i\leq 10^9$).
It is guaranteed that the sum of $n$ of all test cases does not exceed $5 \cdot 10^5$.
Output
For each test case, output the minimum total time in minutes required.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first test case, the necklace will be cut into $3$ parts: $[1,2][3,4][5]$, so the total time is $3$.
In the second test case, the necklace will be cut into $3$ parts: $[5,1][2][3,4]$, Tenzing will cut the strings connecting $(1,2), (2,3)$ and $(4,5)$, so the total time is $a_1+a_2+a_4=7$.