Search Engine Algorithms are mathematical formulations which the search engines use to rank websites on the Search Engine Ranking Pages, also known as SERPs for their relevant keywords. Based on their formulation for ranking different web pages, the search engines analyse each page to decide its positioning on the search results. Every search engine uses its own proprietary ranking algorithm which aims to provide useful and quality results whenever a search query is carried out by users.
In order for your website to rank on the search results, it is necessary that you stay up-to-date with changing search engine algorithms so that you can tweak your website from time to time and keep it high in the search results by following search engine quality guidelines. Search Engines update their algorithms from time to time, and they are never made public.