The Power of Simple Tabulation Hashing

Randomized algorithms are often enjoyed for their simplicity, but the hash functions used to yield the desired theoretical guarantees are often neither simple nor practical. Here we show that the simplest possible tabulation hashing provides unexpectedly strong guarantees. The scheme itself dates back to Carter and Wegman (STOC'77). Keys are viewed as consisting of c characters. We initialize c tables T1, . . . , Tc mapping characters to random hash codes. A key x = (x1, . . . , xq) is hashed to T1[x1]

• Type: Journal
• Year: 2010
• Where: CORR
• Authors: Mihai Patrascu, Mikkel Thorup
• Keywords: CORR 2010, Education, Randomized Algorithms, Simplest Possible Tabulation, Theoretical Guarantees