chore(Java): added exponential search (#523)

Co-authored-by: Ming Tsai <37890026+ming-tsai@users.noreply.github.com>

algorithms/Java/README.md

@@ -44,7 +44,8 @@
 2. [Jump Search](searching/jump-search.java)
 3. [Linear Search](searching/linear-search.java)
 4. [Allocate minimum number of pages](searching/allocate-min-pages.java)
-5. [Interpolation Search](searching/interpolation-search.java)
+5. [Exponential Search](searching/Exponential-search.java)
+6. [Interpolation Search](searching/interpolation-search.java)
 
 ## Sorting
 

algorithms/Java/searching/Exponential-search.java

@@ -0,0 +1,31 @@
+// 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);
+	}
+}