gourav

package test.padovanstring;

public class PadovanString {
public int stringOccurrences(int n, String str){

if(n >= 40)
return -1;
if(str.replaceAll("X|Y|Z","").length()>0)
return -1;
String res=pad(n);
return(res.length() - res.replaceAll(str,"").length())/(str.length());
}
public String pad(int n){
if(n == 0) return "X";
if(n == 1) return "Y";
if(n == 2) return "Z";
else return pad(n-2) + pad(n-3);

}
public static void main(String []args)
{
PadovanString p = new PadovanString();
System.out.println(p.stringOccurrences(21,"YZ"));
}
}