New fastest deterministic 3SUM algorithm hits n^1.9961, matching randomized bound

basedjensen · x · 2026-10-10

A new record for the 3SUM problem: the fastest known deterministic algorithm now runs in n^1.9961 — a 4.5× saving below n² with zero randomness, matching the best randomized bound. The advance builds on the paper "Truly Subquadratic 3SUM and Truly Subcubic APSP via Triangles in Sparse Lopsided Graphs" by Josh Alman and Virginia Vassilevska Williams, which uses triangles in sparse lopsided graphs to yield both subquadratic 3SUM and subcubic APSP results — a major breakthrough in fine-grained complexity.

Original post →

More from Research

Research channel →