Why it matters

X-fast tries give O(log log U) queries. Space heavy.

Advertisement

The architecture

Perfect hash on each level.

Binary search on levels.

O(log log U) query.

X-fast triePerfect hasheach levelBinary searchon levelsQueryO(log log U)Willard 1983; O(U log U) space; precursor to y-fast trie
X-fast trie.
Advertisement

How it works end to end

Willard 1983.

Perfect hashing.

Precursor to y-fast.