static long gen ( int n ) {
  String s = "" ;
  for ( int i = 0 ;
  i < n && s . length ( ) < n ;
  i ++ ) {
    s += s + "1" ;
  };
}

static long gen ( int n ) { String s = " " ; for ( int i = 0 ; i < n && s . length ( ) < n ; i ++ ) { s += s + "1" ; } ; }
(method_declaration (modifiers) type: (integral_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (string_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (identifier))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (string_literal))))))))