chore(Java): added interpolation search (#522)

algorithms/Java/README.md

@@ -44,6 +44,7 @@
 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)
 
 ## Sorting
 

algorithms/Java/searching/interpolation-search.java

@@ -0,0 +1,50 @@
+// Java program to implement interpolation search with recursion
+import java.util.*;
+class GFG {
+
+	// If x is present in arr[0..n-1], then returns index of it, else returns -1.
+	public static int interpolationSearch(int arr[], int lo, int hi, int x)
+	{
+		int pos;
+
+		// Since array is sorted, an element present in array must be in rangedefined by corner
+		if (lo <= hi && x >= arr[lo] && x <= arr[hi]) {
+
+			// Probing the position with keeping uniform distribution in mind.
+			pos = lo + (((hi - lo) / (arr[hi] - arr[lo])) * (x - arr[lo]));
+
+			// Condition of target found
+			if (arr[pos] == x)
+				return pos;
+
+			// If x is larger, x is in right sub array
+			if (arr[pos] < x)
+				return interpolationSearch(arr, pos + 1, hi, x);
+
+			// If x is smaller, x is in left sub array
+			if (arr[pos] > x)
+				return interpolationSearch(arr, lo, pos - 1, x);
+		}
+		return -1;
+	}
+
+	// Driver Code
+	public static void main(String[] args)
+	{
+
+		// Array of items on which search will be conducted.
+		int arr[] = { 10, 12, 13, 16, 18, 19, 20, 21, 22, 23, 24, 33, 35, 42, 47 };
+
+		int n = arr.length;
+
+		// Element to be searched
+		int x = 18;
+		int index = interpolationSearch(arr, 0, n - 1, x);
+
+		// If element was found
+		if (index != -1)
+			System.out.println("Element found at index "+ index);
+		else
+			System.out.println("Element not found.");
+	}
+}