Using hashing to solve the dictionary problem

7 years 2 months ago
Using hashing to solve the dictionary problem
We consider the dictionary problem in external memory and improve the update time of the wellknown buffer tree by roughly a logarithmic factor. For any λ ≥ max{lg lg n, logM/B(n/B)}, we can support updates in time O( λ B ) and queries in time O(logλ n). We also present a lower bound in the cell-probe model showing that our data structure is optimal. In the RAM, hash tables have been use to solve the dictionary problem faster than binary search for more than half a century. By contrast, our data structure is the first to beat the comparison barrier in external memory. Ours is also the first data structure to depart convincingly from the indivisibility paradigm.
John Iacono, Mihai Patrascu
Added 28 Sep 2012
Updated 28 Sep 2012
Type Journal
Year 2012
Where SODA
Authors John Iacono, Mihai Patrascu
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