int[]
A node is represented with a node number, an index to access name code, parent node number, type code, first child index, number of children, child node numbers, first attribute index, number of attributes and attribute node numbers.
Simple Node Object
A node is modeled as a simple class with name code attribute, parent node reference, child node array and attribute set.
Linked Node Object
A node is represented as an object with name code, parent, first child, next sibling, previous sibling and first attribute node reference.
DOM Implementation
Linked int[]
7 integers = 28Bytes
Could be further optimized by encoding the type into the name code or the node number itself. Eg. still 1billion nodes with a 30 bit number.
O(n) child node access
Linked Node Object
A node is represented as an object with name code, parent, first child, next sibling, previous sibling and first attribute node reference.

A node is represented as an integer number, an index to access the name code, parent node number, type code, first child node number, next and previous sibling node number and the first attribute node number.

/livcos.org/data/map/brainstorm/DomImplementation