5 | | In fact, it is a fundamental part of the data structure. It contains ''all'' items ordered by their levels and by there activeness. I.e. it stars with the active items on level 0, then the inactive ones on level 0, then the active ones on level 1, then the inactive ones on level 1 etc. |
6 | | The vectors `_first` and `_last_active` indicates the borders of these intervals on each level. In addition, the map `_where` gives a cross reference to the elements. The values of these vectors are ''pointers'' (`Item *`), and the elements of `_items` are accessed and manipulated through them. |
| 5 | In fact, it is a fundamental part of the data structure. It contains ''all'' items ordered by their levels and by their activeness. I.e. it starts with the active items on level 0, then come the inactive ones on level 0, then the active ones on level 1, then the inactive ones on level 1 etc. |
| 6 | The vectors `_first` and `_last_active` indicate the borders of these intervals on each level. In addition, the map `_where` gives a cross reference to the elements. The values of these vectors are ''pointers'' (`Item *`), and the elements of `_items` are accessed and manipulated through them. |