[[File:Hash table 3 1 1 0 1 0 0 SP.svg|thumb|upright=1.2|Visual representation of a [[hash table]], a [[data structure]] that allows for fast retrieval of information.]]
In [[computer science]], a '''search algorithm''' is an [[algorithm]] (if more than one, algorithms<ref>{{Cite web|last=Davies|first=Dave|date=May 25, 2020|title=How Search Engine Algorithms Work: Everything You Need to Know|url=https://www.searchenginejournal.com/search-engines/algorithms/#whysearc|url-status=live|access-date=27 March 2021|website=Search Engine Journal}}</ref>) designed to solve a [[search problem]]. Search algorithms work to retrieve information stored within particular [[data structure]], or calculated in the [[Feasible region|search space]] of a problem ___domain, with [[Continuous or discrete variable|either discrete or continuous values]]. algorithms are
Although [[Search engine (computing)|search engines]] use search algorithms, they belong to the study of [[information retrieval]], not algorithmics.
While the search problems described above and [[web search]] are both problems in information retrieval, they are generally studied as separate subfields and are solved and evaluated differently. Web search problems are generally focused on filtering and finding documents highly relevant to human queries. Classic search algorithms are evaluated on how fast they can find a solution, and whether the solution found is optimal. Though information retrieval algorithms must be fast, the quality of [[Ranking (information retrieval)|ranking]], and whether good results have been left out and bad results included, is more important.
The appropriate search algorithm often depends on the data structure being searched, and may also include prior knowledge about the data. Search algorithms can be made faster or more efficient by specially constructed database structures, such as [[search tree]]s, [[hash map]]s, and [[database index]]es.{{Sfn|Beame|Fich|2002|p=39}}{{full citation needed|date=April 2021}}{{Sfn|Knuth|1998|loc=§6.5 ("Retrieval on Secondary Keys")}}
