Cashback
题意翻译
给你一个长度为n的数列a和整数c
你需要把它任意分段
每一段假设长度为k，就去掉前$\lfloor\frac{k}{c}\rfloor$ 小的数
最小化剩下的数的和
感谢@xzz_233 提供的翻译
题目描述
Since you are the best Wraith King, Nizhniy Magazin «Mir» at the centre of Vinnytsia is offering you a discount.
You are given an array $ a $ of length $ n $ and an integer $ c $ .
The value of some array $ b $ of length $ k $ is the sum of its elements except for the  smallest. For example, the value of the array $ [3,1,6,5,2] $ with $ c=2 $ is $ 3+6+5=14 $ .
Among all possible partitions of $ a $ into contiguous subarrays output the smallest possible sum of the values of these subarrays.
输入输出格式
输入格式
The first line contains integers $ n $ and $ c $ ( $ 1<=n,c<=100000 $ ).
The second line contains $ n $ integers $ a_{i} $ ( $ 1<=a_{i}<=10^{9} $ ) — elements of $ a $ .
输出格式
Output a single integer — the smallest possible sum of values of these subarrays of some partition of $ a $ .
输入输出样例
输入样例 #1
3 5
1 2 3
输出样例 #1
6
输入样例 #2
12 10
1 1 10 10 10 10 10 10 9 10 10 10
输出样例 #2
92
输入样例 #3
7 2
2 3 6 4 5 7 1
输出样例 #3
17
输入样例 #4
8 4
1 3 4 5 5 3 4 1
输出样例 #4
23
说明
In the first example any partition yields 6 as the sum.
In the second example one of the optimal partitions is $ [1,1],[10,10,10,10,10,10,9,10,10,10] $ with the values 2 and 90 respectively.
In the third example one of the optimal partitions is $ [2,3],[6,4,5,7],[1] $ with the values 3, 13 and 1 respectively.
In the fourth example one of the optimal partitions is $ [1],[3,4,5,5,3,4],[1] $ with the values 1, 21 and 1 respectively.