private static boolean ok ( String last4 ) {
  for ( int i = 0 ;
  i < 4 ;
  i ++ ) {
    char [ ] t = last4 . toCharArray ( ) ;
    if ( i >= 1 ) {
      char buf = t [ i - 1 ] ;
      t [ i - 1 ] = t [ i ] ;
      t [ i ] = buf ;
    }
    if ( String . valueOf ( t ) . indexOf ( "AGC" ) >= 0 ) {
      return false ;
    }
  }
  return true ;
}

private static boolean ok ( String last4 ) { for ( int i = 0 ; i < 4 ; i ++ ) { char [ ] t = last4 . toCharArray ( ) ; if ( i >= 1 ) { char buf = t [ i - 1 ] ; t [ i - 1 ] = t [ i ] ; t [ i ] = buf ; } if ( String . valueOf ( t ) . indexOf ( " AGC " ) >= 0 ) { return false ; } } return true ; }
(method_declaration (modifiers) type: (boolean_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier))) body: (block (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (decimal_integer_literal)) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (array_access array: (identifier) index: (identifier)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (identifier))))) (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) name: (identifier) arguments: (argument_list (string_literal))) right: (decimal_integer_literal))) consequence: (block (return_statement (false)))))) (return_statement (true))))