rootid

//StringBuilder vs String

//quadratic time
public static String reverse(String s)
{
   String rev = "";
   for (int i=s.length();i>=0;i--) {
       rev += s[i];
   }
   return rev;

rootid

//StringBuffer/StringBuilder vs String
//Linear time
public static String[] suffixArray(String s) 
{
 
   int N = s.length();
   String[] suffixes = new String[N];
   for (int i = 0; i < N; i++)
      suffixes[i] = s.substring(i, N);
   return suffixes;