/**
* @param a
* @return
*/
private String convertToString(int a) {
int c;
char m;
StringBuilder ans = new StringBuilder();
// convert the String to int
while (a > 0) {
c = a % 10;
a = a / 10;
m = (char) ('0' + c);
ans.append(m);
}
return ans.reverse().toString();
}