MovingAvg | Topcoder Archive

Problem Statement

When data is collected at regular intervals, trends in the data are sometimes easier to see by looking at a moving average. The moving average of length k at a particular time is the average of the k most recently collected data values. So at time t it is the average of the data reported at times t,t-1,...,t-(k-1). The moving average is not defined at time t unless we have data for the preceding k-1 times.

We have a sequence of data values and want to look at the moving averages of length k of those values. Specifically, we want to know how much the largest moving average exceeds the smallest moving average.

Create a class MovingAvg that contains a method difference that is given k and double[] data. It returns the difference between the largest and smallest moving average of length k in data.

Definition

Class:: MovingAvg
Method:: difference
Parameters:: int, double[]
Returns:: double
Method signature:: double difference(int k, double[] data)
(be sure your method is public)

Notes

The returned value must be accurate to within a relative or absolute value of 1E-9.

Constraints

k will be between 1 and 10, inclusive.
data will contain between k and 50 elements, inclusive.
Each element of data will be between 0.0 and 1000.0 inclusive.

Examples

```
2
```
```
{3,8,9,15}
```
```
Returns: 6.5
```
The moving averages are (3+8)/2, (8+9)/2, and (9+15)/2 which are 5.5, 8.5, and 12.0. So the difference between the largest and smallest is 12.0 - 5.5 = 6.5
```
3
```
```
{17,6.2,19,3.4}
```
```
Returns: 4.533333333333335
```
The moving averages are (17+6.2+19)/3 and (6.2+19+3.4)/3 which are 14.0666666... and 9.533333...
```
3
```
```
{6,2.5,3.5}
```
```
Returns: 0.0
```
There is only 1 moving average of length 3, so the smallest and biggest moving average are the same.

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