public static void main ( String [ ] args ) {
  Scanner scn = new Scanner ( System . in ) ;
  int t = scn . nextInt ( ) ;
  while ( t -- > 0 ) {
    int n = scn . nextInt ( ) ;
    int [ ] arr = new int [ 2 * n ] ;
    HashSet < Integer > hs = new HashSet < > ( ) ;
    boolean [ ] mark = new boolean [ n ] ;
    ArrayList < Integer > al = new ArrayList < > ( ) ;
    for ( int i = 0 ;
    i < 2 * n ;
    i ++ ) {
      arr [ i ] = scn . nextInt ( ) ;
      if ( ! mark [ arr [ i ] - 1 ] ) {
        al . add ( arr [ i ] ) ;
        mark [ arr [ i ] - 1 ] = true ;
      }
    }
    for ( int i = 0 ;
    i < n ;
    i ++ ) System . out . print ( al . get ( i ) + " " ) ;
    System . out . println ( ) ;
  }
}

public static void main ( String [ ] args ) { Scanner scn = new Scanner ( System . in ) ; int t = scn . nextInt ( ) ; while ( t -- > 0 ) { int n = scn . nextInt ( ) ; int [ ] arr = new int [ 2 * n ] ; HashSet < Integer > hs = new HashSet < > ( ) ; boolean [ ] mark = new boolean [ n ] ; ArrayList < Integer > al = new ArrayList < > ( ) ; for ( int i = 0 ; i < 2 * n ; i ++ ) { arr [ i ] = scn . nextInt ( ) ; if ( ! mark [ arr [ i ] - 1 ] ) { al . add ( arr [ i ] ) ; mark [ arr [ i ] - 1 ] = true ; } } for ( int i = 0 ; i < n ; i ++ ) System . out . print ( al . get ( i ) + " ▁ " ) ; System . out . println ( ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (while_statement condition: (parenthesized_expression (binary_expression left: (update_expression (identifier)) right: (decimal_integer_literal))) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (binary_expression left: (decimal_integer_literal) right: (identifier)))))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (boolean_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (boolean_type) dimensions: (dimensions_expr (identifier))))) (local_variable_declaration type: (generic_type (type_identifier) (type_arguments (type_identifier))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) arguments: (argument_list)))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (binary_expression left: (decimal_integer_literal) right: (identifier))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (unary_expression operand: (array_access array: (identifier) index: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal))))) consequence: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (identifier))))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal))) right: (true))))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (string_literal)))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list)))))))