public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int [ ] a = new int [ n ] ;
  for ( int i = 0 ;
  i < a . length ;
  i ++ ) {
    a [ i ] = sc . nextInt ( ) ;
  }
  List < Integer > eventNums = new ArrayList < > ( ) ;
  Set < Integer > left = new HashSet < > ( ) ;
  Set < Integer > entered = new HashSet < > ( ) ;
  int eventNum = 0 ;
  for ( int ai : a ) {
    if ( ai > 0 ) {
      if ( left . contains ( ai ) || entered . contains ( ai ) ) {
        System . out . println ( "-1" ) ;
        return ;
      }
      entered . add ( ai ) ;
    }
    else {
      if ( ! entered . contains ( - ai ) ) {
        System . out . println ( "-1" ) ;
        return ;
      }
      entered . remove ( - ai ) ;
      left . add ( - ai ) ;
    }
    eventNum ++ ;
    if ( entered . isEmpty ( ) ) {
      eventNums . add ( eventNum ) ;
      left . clear ( ) ;
      entered . clear ( ) ;
      eventNum = 0 ;
    }
  }
  if ( eventNum != 0 ) {
    System . out . println ( "-1" ) ;
    return ;
  }
  System . out . println ( eventNums . size ( ) ) ;
  for ( int i = 0 ;
  i < eventNums . size ( ) ;
  i ++ ) System . out . print ( eventNums . get ( i ) + " " ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int [ ] a = new int [ n ] ; for ( int i = 0 ; i < a . length ; i ++ ) { a [ i ] = sc . nextInt ( ) ; } List < Integer > eventNums = new ArrayList < > ( ) ; Set < Integer > left = new HashSet < > ( ) ; Set < Integer > entered = new HashSet < > ( ) ; int eventNum = 0 ; for ( int ai : a ) { if ( ai > 0 ) { if ( left . contains ( ai ) || entered . contains ( ai ) ) { System . out . println ( " - 1" ) ; return ; } entered . add ( ai ) ; } else { if ( ! entered . contains ( - ai ) ) { System . out . println ( " - 1" ) ; return ; } entered . remove ( - ai ) ; left . add ( - ai ) ; } eventNum ++ ; if ( entered . isEmpty ( ) ) { eventNums . add ( eventNum ) ; left . clear ( ) ; entered . clear ( ) ; eventNum = 0 ; } } if ( eventNum != 0 ) { System . out . println ( " - 1" ) ; return ; } System . out . println ( eventNums . size ( ) ) ; for ( int i = 0 ; i < eventNums . size ( ) ; i ++ ) System . out . print ( eventNums . get ( i ) + " ▁ " ) ; }
(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)))) (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 (identifier))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (field_access object: (identifier) field: (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)))))) (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: (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: (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: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (enhanced_for_statement type: (integral_type) name: (identifier) value: (identifier) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))) alternative: (block (if_statement condition: (parenthesized_expression (unary_expression operand: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (unary_expression operand: (identifier)))))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (unary_expression operand: (identifier))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (unary_expression operand: (identifier))))))) (expression_statement (update_expression (identifier))) (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) consequence: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (expression_statement (assignment_expression left: (identifier) right: (decimal_integer_literal))))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (method_invocation object: (identifier) name: (identifier) 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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) 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))))))))