Mo's algorithm was proposed by Mo Tao. Before Mo Tao proposed it, Mo's algorithm had already circulated on a small scale among Codeforces experts, but Mo Tao was the first to systematically summarize it. When Mo Tao proposed it, he analyzed only the ordinary version; through the collective efforts of OIers and ACMers, Mo's algorithm gained several extended versions.
Mo's algorithm can solve a class of offline range-query problems and is extremely versatile. With suitable extensions, it can also handle path queries on trees and support modifications with ease.