3SUM with Preprocessing: Algorithms, Lower Bounds and Cryptographic Applications

Given a set of integers $\{a_1, \ldots, a_N\}$, the 3SUM problem requires finding $a_i, a_j, a_k \in A$ such that $a_i + a_j = a_k$. A preprocessing version of 3SUM, called 3SUM-Indexing, considers an initial offline phase where a computationally unbounded algorithm receives $a_1,\ldots,a_N$ and produces a data structure with $S$ words ...More