Finding plateau in Java Array

Question

I having a really hard time finding a plateau within an array. What I'm looking for is length and location of the longest sequence of equal values where the numbers on both sides are smaller. Now I know there could be two or more valid plateaus with same length ideally I would like to print the plateau with a higher value.

I have created an array[40] and a Random obj. To fill the array, once I have filled it I know I will need a loop to check the indexes. But thats where the confusion comes in. I have tried using a for loop to find the plateau but my results would just increase the value stored within the index. Any points in the right direction I would greatly appreciate it.

import java.util.Random;
public class Plateau {
public static void main(String[]args)
{
    int[] array1 = new int[40];
    Random genrator = new Random();

    for (int i = 0; i < array1.length; i++)
    {
        array1[i] = genrator.nextInt(21 - 1);
    }
    for(int i = 0; i < array1.length; i++)
    {
        System.out.print(array1[i] + " ");
    }
    System.out.println("\n");

    for (int i = 0; i < array1.length; i++)
    {
        if (array1[i] < array1[i] + 1)
        {

            System.out.println(array1[i] + " ");
        }

    }



}

}

Answer 1

In pseudo-code:

V value=first value
P position=1
L length=0
Scan the values from position Q=2
  Compare current value C to V
  If C is less than V
    if this sequence Q-P is longer than L 
      save length as L
      save P as location R
    update V and P to current value
  If C is greater than V
    update V and P to current value

I don't have a compiler for pseudo-code so it might not be exactly right, but it should be a start.

Answer 2

public class plateauv2 {
    
    public static void main(String[] args) {
        int[] arr = {1,1,2,3,4,5,1,2,4,3,3,3,3,3,5,2,2,2,2,31};
        plateau(arr);
    }

    public static void plateau(int arr[]) {
        int longestStartIdx = -1;
        int longestEndIdx = -1;
        
        int currL = 1;
        int maxL = 1;
        int currStartIdx = -1;
        int currEndIdx = -1;    
        for (int i = 0 , j = i + 1; j < arr.length; i++, j++) {
            boolean flag = false;
            if (arr[i] == arr[j]) {
                flag = true;
            } else {
                flag = false;
                currL = 1;
                currStartIdx = j;
            }
            if (flag) {
                currL++;
                currEndIdx=j;
                if (currL > maxL) {
                    maxL = currL;
                    longestStartIdx = currStartIdx;
                    longestEndIdx = currEndIdx;
                }     
            }
        }

        if (longestStartIdx != 1 && longestEndIdx !=1 ) {
               System.out.println("=================================");
               System.out.println("Longest Plateau Lenght: " +maxL );
               System.out.println("Plateau Number: " +arr[longestEndIdx]);
               System.out.println("Plateau starts at Index: " +longestStartIdx ); 
               System.out.println("Plateau ends at Index: "+longestEndIdx);           
               
               System.out.println("======================================");
               System.out.println(""); 
        } else {
            System.out.println("No Plateau Found.");
        }
    }

}