*
   * @since 11.0
   */
  public static String commonSuffix(CharSequence a, CharSequence b) {
    checkNotNull(a);
    checkNotNull(b);

    int maxSuffixLength = min(a.length(), b.length());
    int s = 0;
    while (s < maxSuffixLength && a.charAt(a.length() - s - 1) == b.charAt(b.length() - s - 1)) {
      s++;
    }
    if (validSurrogatePairAt(a, a.length() - s - 1)

   *
   * @since 11.0
   */
  public static String commonSuffix(CharSequence a, CharSequence b) {
    checkNotNull(a);
    checkNotNull(b);

    int maxSuffixLength = min(a.length(), b.length());
    int s = 0;
    while (s < maxSuffixLength && a.charAt(a.length() - s - 1) == b.charAt(b.length() - s - 1)) {
      s++;
    }
    if (validSurrogatePairAt(a, a.length() - s - 1)

        }
        final String suffix = "\n[Referenced documents: " + titles + "]";
        if (suffix.length() <= maxSuffixLength) {
            return suffix;
        }
        if (maxSuffixLength <= 0) {
            return "";
        }
        return suffix.substring(0, maxSuffixLength);
    }

    private static final int MAX_QUERY_LENGTH = 1000;