Preparing NOJ # Array Splitting

2000ms 262144K

## Description:

You are given an array $a_1, a_2, \dots, a_n$ and an integer $k$.

You are asked to divide this array into $k$ non-empty consecutive subarrays. Every element in the array should be included in exactly one subarray. Let $f(i)$ be the index of subarray the $i$-th element belongs to. Subarrays are numbered from left to right and from $1$ to $k$.

Let the cost of division be equal to $\sum\limits_{i=1}^{n} (a_i \cdot f(i))$. For example, if $a = [1, -2, -3, 4, -5, 6, -7]$ and we divide it into $3$ subbarays in the following way: $[1, -2, -3], [4, -5], [6, -7]$, then the cost of division is equal to $1 \cdot 1 - 2 \cdot 1 - 3 \cdot 1 + 4 \cdot 2 - 5 \cdot 2 + 6 \cdot 3 - 7 \cdot 3 = -9$.

Calculate the maximum cost you can obtain by dividing the array $a$ into $k$ non-empty consecutive subarrays.

## Input:

The first line contains two integers $n$ and $k$ ($1 \le k \le n \le 3 \cdot 10^5$).

The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($|a_i| \le 10^6$).

## Output:

Print the maximum cost you can obtain by dividing the array $a$ into $k$ nonempty consecutive subarrays.

## Sample Input:

 5 2 -1 -2 5 -4 8

## Sample Output:

 15

## Sample Input:

 7 6 -3 0 -1 -2 -2 -4 -1

## Sample Output:

 -45

## Sample Input:

 4 1 3 -1 6 0

## Sample Output:

 8

Info Provider CodeForces

Code CF1175D

Tags

greedysortings

Submitted 35

Passed 22

AC Rate 62.86%

Date 07/21/2019 13:41:18

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