// Java program to find an element x in a sorted array using Exponential search.
import java.util.Arrays;

class ExponentialSearch
{
	// Returns position of first occurrence of x in array
	static int exponentialSearch(int arr[], int n, int x)
	{
		// If x is present at first location itself
		if (arr[0] == x)
			return 0;
	
		// Find range for binary search by repeated doubling
		int i = 1;
		while (i < n && arr[i] <= x) 
            i = i*2;
	
		// Call binary search for the found range.
		return Arrays.binarySearch(arr, i/2, Math.min(i, n-1), x);
	}
	
	// Driver code
	public static void main(String args[])
	{
		int arr[] = {2, 3, 4, 10, 40};
		int x = 10;
		int result = exponentialSearch(arr, arr.length, x);
		
		System.out.println((result < 0) ? "Element is not present in array" : "Element is present at index " + result);
	}
}