ArithmeticalMean | Topcoder Archive

Problem Statement

You are given a int[] elements. If the arithmetic mean of a non-empty subset of elements is between L and H, inclusive, the subset is considered "good". A subset of a int[] is obtained by removing 0 or more elements from the int[]. Return the number of "good" subsets.

Definition

Class:: ArithmeticalMean
Method:: howMany
Parameters:: int[], int, int
Returns:: long
Method signature:: long howMany(int[] elements, int L, int H)
(be sure your method is public)

Constraints

elements will contain between 1 and 36 elements, inclusive.
Each element of elements will be between -25000000 and 25000000, inclusive.
Each element of elements will be distinct.
L and H will each be between -25000000 and 25000000, inclusive.
L will not be greater than H.

Examples

```
{10,1,3}
```
```
2
```
```
6
```
```
Returns: 4
```
All possible arithmetic means are: 1, 2, 3, 14/3, 11/2, 13/2, 10. Four of them (2, 3, 14/2, 11/2) make "good" subsets.
```
{0}
```
```
-1
```
```
0
```
```
Returns: 1
```
There is just one subset and it's "good".
```
{0}
```
```
100
```
```
100
```
```
Returns: 0
```
Same one subset but it's not "good".
```
{1,2,3,4,5,6,7,8,9,10}
```
```
3
```
```
7
```
```
Returns: 949
```

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