Hashing for GATE CS

By : Manglika Tripathi

Updated : Feb 26, 2021, 16:35

Hashing is a method used to build, search, or delete the data from a given table using a hash table. A hash table is a collection of arrays stored in the database used to insert or search a given data. The hash function is used for hashing. A hash function is a method of finding the index for the table using a key. Several resources, for example, a hashing book, can help to get a better understanding of these concepts.

The students can look at the hashing GATE CS questions and answers pdf to begin their preparation for the ISRO, GATE, BARC, and many other computer science engineering exams. The online hashing quiz helps students improve the scores in the exam.

Important Hashing Topics for GATE CS



Load factor

Load factor = No of items in table/size of table

Division method for hashing

It is a method in which the key “k” is mapped to the m slot using the remainder obtained by dividing k by m.

Mid-square method for hashing

It is a method in which the key “k” is mapped to the m slot using the middle digits obtained by calculating k2.

Folding method for hashing

It is a method in which the key is divided into sections of equal length and then added together.

Radix hashing

In this, we convert the base of the number and divide it further by the address.

Separate chaining

Separate chaining is a collision resolution technique in which the hash key is stored in a linked list, connected to the slot like a chain.

Open addressing

In this type of collision resolution technique, the data is stored in the hash table. The size of this hash table is greater than the number of keys.

Tips to Solve/Prepare for Hashing Questions in GATE

  • Some important formulas to remember:

h(k) = k mod m (for division method)

h(k) is the middle digits of k2(for mid-square method)

The average length of chain =NM, where N = array size and M = number of linked lists.

You can also refer to hashing notes for GATE CS pdf for more shortcuts.

  • Probability (two keys that will hash at the same slot) =1N
  • It helps if the student takes the hashing online test on the internet to improve the overall scores.
  • Also, take hashing GATE questions from previous year papers to understand the type of questions asked and be prepared to handle them efficiently.

Importance of Hashing in GATE CS Exam

  • Hashing MCQ questions contribute 4-6 marks in the exam. More practice on these types of questions helps to score better marks. 
  • This topic contains simple numerical that can be solved by applying simple formulae. It increases the chances of scoring better marks.
  • Regular practice by giving a hashing quiz on the internet will improve the student's rank.
  • The hashing GATE CS syllabus is small and requires less time for preparation.

Most Recommended Books for Hashing for GATE

By referring to the below books, you can understand all the concepts and appear for the exams with confidence.

Book Name


Introduction to Algorithm

Thomas H. Cormen

Computer Algorithm

Horowitz & Sahni

Why Prepare Hashing from BYJU'S Exam Prep?

BYJU'S Exam Prep is the perfect destination for all the students who are preparing for competitive exams like GATE CS. BYJU'S Exam Prep provides hashing study material for GATE CS, designed by their team of experienced mentors. Here at BYJU'S Exam Prep, the entire team works as a community to help each other achieve their goals. BYJU'S Exam Prep also provides the best hashing GATE notes that the student can purchase to understand the correct perspective. You can also participate in a hashing online quiz to improve their scores and increase their chance of getting admission to your desired college. They can also refer to the hashing MCQ pdf for practice.

Frequently Asked Questions

Q. From where can I get notes for preparing the hashing topic for GATE CS exams?

You can easily download hashing notes for CS  from BYJU'S Exam Prep and start with your preparation. It would help if you went through them to get an understanding of the concepts.

Q. Can a ME student appear for GATE CS exams?

Yes, you can appear for the GATE CS exams. It would help if you dedicated more time to the topic hashing for computer science to compete with other CS students. You can also refer to the hashing syllabus for GATE to understand the critical topics you need to cover.

Q. What are the types of questions asked for the topic hashing in GATE exams?

For this, you need to refer to the hashing GATE syllabus and look at all the concepts that need to be covered. You are usually asked to find a hashing function using the different methods of hashing.

Q. How can I solve the questions from hashing in less time?

It helps if you practice many questions to improve your speed or take the help of hashing online tests and enhance your results.

Q. What are the hashing topics for GATE CS?

To get a brief idea of the topics that are covered, you may visit BYJU'S Exam Prep. It gives you a brief outline of all the concepts that are covered. You can also download the necessary study material from there.