static void generate_random_permutation ( int l , int r ) {
  if ( l > r ) return ;
  int n = give_random_number ( l , r ) ;
  permutation . add ( n ) ;
  generate_random_permutation ( l , n - 1 ) ;
  generate_random_permutation ( n + 1 , r ) ;
}

static void generate_random_permutation ( int l , int r ) { if ( l > r ) return ; int n = give_random_number ( l , r ) ; permutation . add ( n ) ; generate_random_permutation ( l , n - 1 ) ; generate_random_permutation ( n + 1 , r ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (return_statement)) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation name: (identifier) arguments: (argument_list (identifier) (identifier))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) (expression_statement (method_invocation name: (identifier) arguments: (argument_list (identifier) (binary_expression left: (identifier) right: (decimal_integer_literal))))) (expression_statement (method_invocation name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)) (identifier))))))