The Pizza Eating Contest

2.6

5 votes
Problem

You have given an array A containing weights of N pizzas. You have to eat exactly 4 pizzas each day. When you eat pizzas of weights X, Y, Z, and W where XYZW, you gain weight equal to Z (i.e. 2nd minimum value of the group), for example- suppose you pick 4 value [7, 4, 3, 3] so you will gain weight 3.

 

Calculate the maximum total weight you can gainby eating the pizzas optimally each day. As the answer could be very large, print it modulo 109+7

 

 


Constraints

  • 1N1051A[i]105

Input Format

The first line contains an integer, N, denoting the number of elements in A.

Each line i of the N subsequent lines (where 0 ≤ i < N) contains an integer describing Ai.

Output format

Print  a single integer modulo 109+7

Sample Input
8
1
3
4
1
5
1
5
3
Sample Output
5
Time Limit: 1
Memory Limit: 256
Source Limit:
Explanation

Pizza weights are [1,3,4,1,5,1,5,3].  You can eat [1,1,1,3] and [3,4,5,5] in batches and gain 1 + 4 = 5 weight.

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