# Double Hashing Multiple choice Questions and Answers (MCQs)

## Click on any option to know the CORRECT ANSWERS

 Question 1
Double hashing is one of the best methods available for open addressing.
 A True B False

Question 1 Explanation:
Double hashing is one of the best methods for open addressing because the permutations produced have many characteristics of randomly chosen permutations.

 Question 2
What is the hash function used in Double Hashing?
 A (h1(k) - i*h2(k))mod m B h1(k) + h2(k) C (h1(k) + i*h2(k))mod m D (h1(k) + h2(k))mod m

Question 2 Explanation:
Double hashing uses a hash function of the form (h1(k) + i*h2(k))mod m where h1 and h2 are auxiliary hash functions and m is the size of the hash table.

 Question 3
On what value does the probe sequence depend on?
 A c1 B k C c2 D m

Question 3 Explanation:
The probe sequence depends in upon the key k since the initial probe position, the offset or both may vary.

 Question 4
The value of h2(k) can be composite relatively to the hash table size m.
 A True B False

Question 4 Explanation:
The value h2(k) must be relatively prime to the hash table size m for the entire hash table to be searched. It can be ensured by having m in powers of 2 and designing h2 so that it produces an odd number.

 Question 5
What are the values of h1(k) and h2(k) in the hash function?
 A h1(k) = m mod k h2(k) = 1+ (m' mod k) B h1(k) = 1 + (m mod k) h2(k) = m' mod k C h1(k) = 1+ (k mod m) h2(k) = k mod m D h1(k) = k mod m h2(k) = 1+ (k mod m')