// A Java program to find a local minima in an array

import java.io.*;

class GFG

{

    // A binary search based function that returns

    // index of a local minima.

    public static int localMinUtil(int[] arr, int low,

                                   int high, int n)

    {

        // Find index of middle element

        int mid = low + (high - low) / 2;

         // Compare middle element with its neighbours

        // (if neighbours exist)

        if(mid == 0 || arr[mid - 1] > arr[mid] && mid == n - 1 ||

           arr[mid] < arr[mid + 1])

                return mid;

        // If middle element is not minima and its left

        // neighbour is smaller than it, then left half

        // must have a local minima.

        else if(mid > 0 && arr[mid - 1] < arr[mid])

                return localMinUtil(arr, low, mid - 1, n);

        // If middle element is not minima and its right

        // neighbour is smaller than it, then right half

        // must have a local minima.

        return localMinUtil(arr, mid + 1, high, n);

    }

    // A wrapper over recursive function localMinUtil()

    public static int localMin(int[] arr, int n)

    {

        return localMinUtil(arr, 0, n - 1, n);

    }

    public static void main (String[] args)

    {

        int arr[] = {4, 3, 1, 14, 16, 40};

        int n = arr.length;

        System.out.println("Index of a local minima is " + localMin(arr, n));

    }

}

//This code is contributed by Dheerendra Singh