Added algorithm in Java - InterpolationSearch. Ref #1

Searching/InterpolationSearch.java

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+//Java program to implement interpolation search
+public class InterpolationSearch {
+
+	// Array of items 
+	static int arr[] = new int[] { 10, 11, 13, 17, 18, 19, 20, 21, 22, 23, 27, 32, 35, 41, 45 };
+
+	// If x is present in arr[0..n-1], then it will return index of it, else -1.
+	static int interpolationSearch(int x) {
+		// Find indexes of two corners
+		int lo = 0, hi = (arr.length - 1);
+
+		// Since array is sorted, an element present
+		// in array must be in range defined by corner
+		while (lo <= hi && x >= arr[lo] && x <= arr[hi]) {
+
+			if (lo == hi) {
+				if (arr[lo] == x)
+					return lo;
+				return -1;
+			}
+
+			// Probing the position with keeping
+			// uniform distribution in mind.
+
+			int 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 upper part
+			if (arr[pos] < x)
+				lo = pos + 1;
+
+			// If x is smaller, x is in the lower part
+			else
+				hi = pos - 1;
+		}
+		return -1;
+	}
+
+	// Driver method
+	public static void main(String[] args) {
+		int x = 18; // Element to be searched
+		int index = interpolationSearch(x);
+
+		// If element was found
+		if (index != -1)
+			System.out.println("Element found at index " + index);
+		else
+			System.out.println("Element not found.");
+	}
+}