inverted index

An inverted index is a data structure used to efficiently find information in a collection of documents, like a search engine. Instead of listing documents and what words they contain, it flips this around, creating a list of words and pointing to all the documents that include each word. For example, if you search for "apple," the inverted index quickly shows you all documents that mention "apple," rather than scanning each document one by one. This helps speed up search results, making it easier to find relevant information quickly in large sets of data.