public:

int numDistinct(string S,string T){

int slen =S.length();

int tlen = T.length();

int number[slen+1][tlen+1];

number[0][0] = 1;

if(S.size() < T.size()){

return 0;

}

for(int i = 1;i <= S.size(); i++){

number[i][0] = 1;

}

for(int j = 1;j <= T.size();j++){

number[0][j] = 0;

}

//number[0] = 1;

for(int i = 1;i <= S.size();i++){

for(int j =1;j <= T.size();j++){

if(S[i - 1] == T[j - 1])

number[i][j] = number[i - 1][j - 1]+number[i - 1][j];

else{

number[i][j] = number[i - 1][j];

}

}

}

return number[slen][tlen];

}