Preparing NOJ

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.

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 $$$a_1, a_2, \dots, a_n$$$ ($$$ |a_i| \le 10^6$$$).

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

5 2 -1 -2 5 -4 8

15

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

-45

4 1 3 -1 6 0

8

Info

Provider CodeForces

Origin Educational Codeforces Round 66 (Rated for Div. 2)

Code CF1175D

Tags

greedysortings

Submitted 35

Passed 22

AC Rate 62.86%

Date 07/21/2019 13:41:18

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