static boolean validateStackSequence ( int pushed [ ] , int popped [ ] , int len ) {
  int j = 0 ;
  Stack < Integer > st = new Stack < > ( ) ;
  for ( int i = 0 ;
  i < len ;
  i ++ ) {
    st . push ( pushed [ i ] ) ;
    while ( ! st . empty ( ) && j < len && st . peek ( ) == popped [ j ] ) {
      st . pop ( ) ;
      j ++ ;
    }
  }
  return j == len ;
}

static boolean validateStackSequence ( int pushed [ ] , int popped [ ] , int len ) { int j = 0 ; Stack < Integer > st = new Stack < > ( ) ; for ( int i = 0 ; i < len ; i ++ ) { st . push ( pushed [ i ] ) ; while ( ! st . empty ( ) && j < len && st . peek ( ) == popped [ j ] ) { st . pop ( ) ; j ++ ; } } return j == len ; }
(method_declaration (modifiers) type: (boolean_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier) dimensions: (dimensions)) (formal_parameter type: (integral_type) name: (identifier) dimensions: (dimensions)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (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: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (identifier))))) (while_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (unary_expression operand: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) right: (binary_expression left: (identifier) right: (identifier))) right: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (array_access array: (identifier) index: (identifier))))) body: (block (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (expression_statement (update_expression (identifier))))))) (return_statement (binary_expression left: (identifier) right: (identifier)))))