public int numDistinct(String s,String t){

int[][] meme = new int[t.length()+1][s.length()+1];

for (int j = 0; j <= s.length() ; j++) {

meme[0][j] = 1;

}

for (int i = 0; i < t.length(); i++) {

for (int j = 0; j < s.length(); j++) {

if (t.charAt(i) == s.charAt(j)){

meme[i+1][j+1] = meme[i][j] + meme[i+1][j];

}else {

meme[i+1][j+1] = meme[i+1][j];

}

}

}

return meme[t.length()][s.length()];

}

public static void main(String[] args) {

String s = "rabbbit";

String t = "rabbit";

NumDistinct numDistinct = new NumDistinct();

int r = numDistinct.numDistinct(s,t);

System.out.println(r);

}