In computer science, the Hunt–McIlroy algorithm is a solution to the longest common subsequence problem. It was one of the first non-heuristic algorithms used in diff. To this day, variations of this algorithm are found in incremental version control systems, wiki engines, and molecular phylogenetics research software.
The research accompanying the final version of Unix diff, written by Douglas McIlroy, was published in the 1976 paper "An Algorithm for Differential File Comparison", co-written with James W. Hunt, who developed an initial prototype of diff.[1]