CF735B.Urbanization

普及/提高-

通过率:0%

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题目描述

Local authorities have heard a lot about combinatorial abilities of Ostap Bender so they decided to ask his help in the question of urbanization. There are nn people who plan to move to the cities. The wealth of the ii of them is equal to aia_{i} . Authorities plan to build two cities, first for n1n_{1} people and second for n2n_{2} people. Of course, each of nn candidates can settle in only one of the cities. Thus, first some subset of candidates of size n1n_{1} settle in the first city and then some subset of size n2n_{2} is chosen among the remaining candidates and the move to the second city. All other candidates receive an official refuse and go back home.

To make the statistic of local region look better in the eyes of their bosses, local authorities decided to pick subsets of candidates in such a way that the sum of arithmetic mean of wealth of people in each of the cities is as large as possible. Arithmetic mean of wealth in one city is the sum of wealth aia_{i} among all its residents divided by the number of them ( n1n_{1} or n2n_{2} depending on the city). The division should be done in real numbers without any rounding.

Please, help authorities find the optimal way to pick residents for two cities.

输入格式

The first line of the input contains three integers nn , n1n_{1} and n2n_{2} ( 1<=n,n1,n2<=1000001<=n,n_{1},n_{2}<=100000 , n1+n2<=nn_{1}+n_{2}<=n ) — the number of candidates who want to move to the cities, the planned number of residents of the first city and the planned number of residents of the second city.

The second line contains nn integers a1,a2,...,ana_{1},a_{2},...,a_{n} ( 1<=ai<=1000001<=a_{i}<=100000 ), the ii -th of them is equal to the wealth of the ii -th candidate.

输出格式

Print one real value — the maximum possible sum of arithmetic means of wealth of cities' residents. You answer will be considered correct if its absolute or relative error does not exceed 10610^{-6} .

Namely: let's assume that your answer is aa , and the answer of the jury is bb . The checker program will consider your answer correct, if .

输入输出样例

  • 输入#1

    2 1 1
    1 5
    

    输出#1

    6.00000000
    
  • 输入#2

    4 2 1
    1 4 2 3
    

    输出#2

    6.50000000
    

说明/提示

In the first sample, one of the optimal solutions is to move candidate 11 to the first city and candidate 22 to the second.

In the second sample, the optimal solution is to pick candidates 33 and 44 for the first city, and candidate 22 for the second one. Thus we obtain (a3+a4)/2+a2=(3+2)/2+4=6.5(a_{3}+a_{4})/2+a_{2}=(3+2)/2+4=6.5

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