From 373bb27e05488f0bab425f826d6d6c0ebdedbb39 Mon Sep 17 00:00:00 2001
From: Mani Manasa Mylavarapu <mamylava@microsoft.com>
Date: Sat, 21 Oct 2017 18:05:47 +0530
Subject: [PATCH] Added karatsuba algorithm for multiplying large numbers fixes
 #96

---
 Others/Karatsuba.java | 53 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 Others/Karatsuba.java

diff --git a/Others/Karatsuba.java b/Others/Karatsuba.java
new file mode 100644
index 000000000000..99780f9de7a6
--- /dev/null
+++ b/Others/Karatsuba.java
@@ -0,0 +1,53 @@
+package Others;
+
+/**
+ *    Java Program to Implement Karatsuba Multiplication Algorithm.
+ *    Mainly used for multiplication of large numbers.
+ *    @author mani manasa mylavarapu
+ **/
+
+import java.util.Scanner;
+
+/** Class Karatsuba **/
+public class Karatsuba {
+	/** Function to multiply two large numbers **/
+	public long multiply(long x, long y) {
+		int size1 = getNumberOfDigits(x);
+		int size2 = getNumberOfDigits(y);
+		int N = Math.max(size1, size2);
+		if (N < 10)
+			return x * y;
+		N = (N / 2) + (N % 2);
+		long m = (long) Math.pow(10, N);
+		long b = x / m;
+		long a = x - (b * m);
+		long d = y / m;
+		long c = y - (d * N);
+		long z0 = multiply(a, c);
+		long z1 = multiply(a + b, c + d);
+		long z2 = multiply(b, d);
+
+		return z0 + ((z1 - z0 - z2) * m) + (z2 * (long) (Math.pow(10, 2 * N)));
+	}
+
+	public int getNumberOfDigits(long num) {
+		int ctr = 0;
+		while (num != 0) {
+			ctr++;
+			num /= 10;
+		}
+		return ctr;
+	}
+
+	/** Main function for testing **/
+	public static void main(String[] args) {
+		Scanner scan = new Scanner(System.in);
+		Karatsuba karat = new Karatsuba();
+
+		System.out.println("Enter two numbers\n");
+		long num1 = scan.nextLong();
+		long num2 = scan.nextLong();
+		long product = karat.multiply(num1, num2);
+		System.out.println("\nProduct result is : " + product);
+	}
+}
\ No newline at end of file