added interpolationSearch.java

Searches/interpolationSearch.java

@@ -0,0 +1,53 @@
+
+class Test
+{
+	// Array of items on which search will
+	// be conducted.
+	static int arr[] = new int[]{10, 12, 13, 16, 18, 19, 20, 21, 22, 23,
+										24, 33, 35, 42, 47};
+	
+	// If x is present in arr[0..n-1], then returns
+	// index of it, else returns -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])
+		{
+			// 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 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.");
+	}
+}
+