#4757. [Usaco2017 Jan]Building a Tall Barn

题目描述

Farmer John is building a brand new, N-story barn, with the help of his KK cows (1≤N≤K≤1012 and N
≤10^5). To build it as quickly as possible, he needs your help to figure out how to allocate work a
mong the cows.Each cow must be assigned to work on exactly one specific floor out of the N total flo
ors in the barn, and each floor must have at least one cow assigned to it. The iith floor requires a
iai units of total work, and each cow completes one unit of work per hour, so if cc cows work on flo
or i, it will be completed in ai/c units of time. For safety reasons, floor ii must be completed bef
ore construction can begin on floor i+1Please compute the minimum total time in which the barn can b
e completed, if the cows are allocated to work on floors in an optimal fashion. Output this number r
ounded to the nearest integer; it is guaranteed that the solution will be more than 0.1 from the bou
ndary between two integers.

输入格式

The first line of input contains N and K.
The next N lines contain a1…aN, each a positive integer of size at most 1012

输出格式

Please output the minimum time required to build the barn, rounded to the nearest integer.

样例输入

``````
2 5
10
4``````

样例输出

``````
5``````