The MountainJohn Latimer

And

Kyle Whittall

Does it have a peak?

Are all values in the array increasing before the peak?

Are all values in the array decreasing after the peak?

Is the array a mountain?

If so….You have a mountain!

A high point in an array.

Example:

1, 2, 3, 4, 5, 4, 3, 2, 1

A peak is…

5

It is a mountain range!

If it does not have a single mountain…

1 2 31

3 2 2 3 3 21

23

21

Has multiple peaks…

The numbers are not only increasing and decreasing before and after one peak.

Example:

A mountain range…

0

2

4

6

8

C

Determine a peak index…

The peak index is the element whose value is greater than the value immediately before it and also greater than the value immediately following it.

The first step…

0

1

2

3

4

5

6

Series 1

Column2

Column1

The peak index here is 5

Determine if all values leading up to a peak are increasing

The second step is to…

Check that all values following the peak are decreasing

The third step is to…

There is a peak if all values before the highest number are increasing and all values following the highest number are decreasing

The code required for a mountain class…

public static int getPeakIndex(int[] arr)

{

// part a

}

To determine if all values after the peak are decreasing…

Next use a for loop to vary through the array

Use an if stmt to contrast i and i-1

You must then add to the if stmt to make it compare i and i+1

If the program finds a peak return that value

If the program does not find a peak have it return -1

Last is the return