I have posts with the following categories:

A category that is a year(2017,2018...2022), a category that is type:(worldwide,Europe, local)

I am trying to give users in the frontend advanced search ability they have two multiselect dropdown, they can pick a year or several. and a type. (both of these are technically categories)

For example `select post from cat 2017` **or** `cat 2018` **AND** that are (`cat=Europe` **or** `cat=local`)`

I am having trouble mixing the "and" and "or" efficiently... in `get_posts`.

For instance I can do something like:

```php
$posts = get_posts(array( 'category__and' => array(1,10) ));  // assuming 10=category Europe, 1 =category 2016,
```

So I just do a loop like 

    Foreach $year in list of years:
      foreach $type in list of types
         get_posts(array( 'category__and' => array($year,$type) ));

Is there a more efficient way to combine my conditions?

Thanks