An inverted list is a data structure that consists of non-overlapping numeric ranges recorded in an array that is sorted in ascending order. The starting point of each range is stored in odd indexes, while the end point is in even indexes. To determine if a number falls within a range, a binary search algorithm is used.
For instance, the following inverted list represents the ranges 10–14, 25–37, and 37–42: 10–15, 25–26, 37–43. Performing operations like union, intersection, set difference, negation, etc. are relatively easy and can be done using linear algorithms.
Typically used in computer science and information retrieval, an inversion list is a list of bits that store positions of each changeover between 0 and 1 bits. It is also known as the inverted index by some authors, and the Perl InversionList, which is written by Teodor Ziatanov, is a classic example of its implementation.
FAQ
What is an inverted list used for?
Inverted lists are typically used in computer science and information retrieval systems to facilitate efficient searching of large datasets. They are particularly useful in text search applications, where they allow for easier indexing and retrieval of information.
How is an inverted list implemented?
An inverted list can be implemented as an array of non-overlapping numeric ranges that are sorted in ascending order. The starting point of each range is stored in odd indexes, while the end point is in even indexes. A binary search algorithm is used to determine if a given number falls within a range.
What operations can be performed on an inverted list?
Common operations that can be performed on an inverted list include union, intersection, set difference, negation, among others. These operations are usually performed using linear algorithms.
Conclusion
Inverted lists are an essential data structure used in many applications, especially in information retrieval systems. They are efficient and allow for easy indexing and retrieval of information. Understanding the implementation and use cases of inverted lists can aid in developing better search algorithms and improving information retrieval systems’ efficiency.
