Storing a Trie with Compact and Predictable Space

Abstract

This paper proposed a storing approach for trie structures, called coordinate hash trie. The basic idea is using a global hash table with a special hash function to store all edges of a trie. For a trie with $n$ nodes and an alphabet with size $m$, the execution time of finding, inserting and deleting a child node, is $O(1)$ for the average case, $O(m)$ for the worst case. The space used by this approach is $O(n)$, unrelated to $m$. The constant of space consumption is predictable, with no need for reallocation or resizing. In addition, this approach is very easy to implement.