Rabin-Karp's Algorithm

A Complete Guide to the Rabin-Karp Algorithm

A hash function is used by the Rabin-Karp algorithm, a string-searching technique, to more effectively search for substrings inside a longer string. As it requires fewer comparisons to discover a match than the conventional method of comparing each sub-string with the pattern, this technique is a significant improvement. We'll get into the specifics of the Rabin-Karp algorithm's operation, implementation, and advantages over alternative string-searching algorithms in this post.

What is the Rabin-Karp Algorithm?

The Rabin-Karp algorithm is a string-searching formula that compares substrings to a given pattern using a hash function.

The algorithm's premise is that comparing two hash values rather than two substrings is quicker. It is clear that the sub-strings are not equal if the hash values are not equal, and it is likely that they are equal if the hash values are equal, but more comparison is required to be sure.

How does the Rabin-Karp Algorithm work?

In the beginning of the Rabin-Karp algorithm, a very big prime number, p, and a random number, x, between 1 and p-1, are chosen.

Get quality help now
Writer Lyla
Writer Lyla
checked Verified writer

Proficient in: Computer Science For Progress

star star star star 5 (876)

“ Have been using her for a while and please believe when I tell you, she never fail. Thanks Writer Lyla you are indeed awesome ”

avatar avatar avatar
+84 relevant experts are online
Hire writer

The random number is used to select the specific hash function, while the prime number is used to select a random polynomial hash function from the family. The pattern's hash value and the hash values of all the text's substrings are calculated using the polynomial hash function. The algorithm then compares the hash values for each of the text's sub-strings. The algorithm advances to the subsequent sub-string if the hash values are not identical.

Get to Know The Price Estimate For Your Paper
Topic
Number of pages
Email Invalid email

By clicking “Check Writers’ Offers”, you agree to our terms of service and privacy policy. We’ll occasionally send you promo and account related email

"You must agree to out terms of services and privacy policy"
Write my paper

You won’t be charged yet!

The approach uses the AreEqual function to determine whether the sub-strings are equal if the hash values are equal. The location of the sub-string is added to the list of positions if the sub-strings are equal, and the algorithm moves on to the following sub-string.

Rabin-Karp algorithm implementation

The Rabin-Karp algorithm is basic to use and has a clear flow. Choosing a huge prime number, p, and a random number, x, between 1 and p-1, is the first stage. The pattern's polynomial hash, which won't alter throughout the method, is computed next. The algorithm then iterates through the text's sub-strings, computing each one's hash value using the PolyHash technique. The method moves on to the next sub-string if the hash values of the pattern and the sub-string do not match. The approach uses the AreEqual function to determine whether the sub-strings are equal if the hash values are equal. The method moves on to the next sub-string if the sub-strings are equal, at which point the position of the sub-string is added to the list of positions.

Advantages of the Rabin-Karp Algorithm

Compared to other string-searching algorithms, the Rabin-Karp algorithm has a number of benefits. First off, it performs more quickly than the conventional method of comparing each sub-string to the pattern. Furthermore, because the likelihood of a false alert is proportional to the length of the pattern over the huge prime number p, it is extremely unlikely. Thirdly, because the technique is simple to use, it is a fantastic option for beginners who are just learning about string-searching algorithms.

Updated: Oct 11, 2024
Cite this page

Rabin-Karp's Algorithm. (2023, Aug 04). Retrieved from https://studymoose.com/rabin-karps-algorithm-essay

Rabin-Karp's Algorithm essay
Live chat  with support 24/7

👋 Hi! I’m your smart assistant Amy!

Don’t know where to start? Type your requirements and I’ll connect you to an academic expert within 3 minutes.

get help with your assignment