Merge pull request #17 from joybanerjee08/master

Karatsuba in Java

Author: Bhrigu Kansra

multiplication/karatsuba.java

@@ -0,0 +1,22 @@
+class Main {
+  public static void main(String[] args) {
+    System.out.print(karatsuba (923,1723));
+  }
+  private static int karatsuba(int x, int y){
+    if (String.valueOf(x).length()==1 || (String.valueOf(y).length()==1)){
+		return x*y;
+    }
+	  else{
+		int n = Math.max(String.valueOf(x).length(),String.valueOf(y).length());
+		int z = n / 2;
+		int a = x /(int) Math.pow(10, z);
+		int b = x %(int) Math.pow(10, z);
+		int c = y /(int) Math.pow(10, z);
+		int d = y %(int) Math.pow(10, z);
+		int ac = karatsuba(a,c);
+		int bd = karatsuba(b,d);
+		int adbc = karatsuba(a+b,c+d) - ac - bd;
+		return ac * (int)Math.pow(10, (2*z)) + (adbc * (int)Math.pow(10, z)) + bd;
+    }
+  }
+}