Practice hashing Quizzes
Enhance your hashing skills with carefully curated quizzes designed to improve concept clarity and real-world application. Each question reinforces key principles through active practice. Ideal for students and professionals, these quizzes help you learn faster, stay sharp and strengthen your overall technical expertise.
Explore All hashing Quizzes
Learn hashing step by step with interactive quizzes designed for beginners and learners revising key concepts. Build a strong foundation with clear, structured practice in hashing.
Question 1
Which of the following properties is essential for a good hash function?
1
It must produce only prime numbers
2
It must be slow to compute
3
It should generate the same hash for different inputs
4
It should distribute keys uniformly
Question 2
What is a "collision" in hashing?
1
When a hash function fails to generate a unique key
2
When a hash table runs out of space
3
When two different inputs produce the same hash value
4
When two hash functions produce the same output
Question 3
Which of the following is NOT a collision resolution technique?
1
Double Hashing
2
Linear Probing
3
Separate Chaining
4
Quick Sorting
Question 4
In open addressing, which of the following techniques involves checking the next available slot sequentially?
1
Separate Chaining
2
Double Hashing
3
Linear Probing
4
Quadratic Probing
Question 5
Which hash function is commonly used for cryptographic applications?
1
MD5
2
SHA-256
3
CRC32
4
All of the above
Question 6
Which of the following is NOT a property of a cryptographic hash function?
1
Deterministic output
2
Avalanche effect
3
Pre-image resistance
4
Fast reversibility
Question 7
Which of the following best describes hashing?
1
A technique to sort data efficiently
2
A method for compressing data
3
A method to convert data into a fixed-size value for fast retrieval
4
A method for encrypting data securely
Question 8
Double hashing uses
1
Two keys for one value
2
A hash and an encryption function
3
Two hash tables
4
Two hash functions to compute probe sequences
Question 9
If the hash table size is m, which of the following ensures minimal collisions?
1
Choosing m as an even number
2
Choosing m equal to 2ⁿ
3
Choosing m as a prime number
4
Choosing m as a multiple of 10
Question 10
In open addressing, primary clustering occurs mostly in which probing method?
1
Separate chaining
2
Quadratic probing
3
Linear probing
4
Double hashing
Question 11
Which hashing scheme uses a random choice of hash function from a family to ensure good average performance regardless of the input?
1
Division method
2
Universal hashing
3
Open addressing
4
Multiplication method
Question 12
What is the expected time complexity of search in a well-distributed hash table using chaining with load factor α = n/m?
1
O(n)
2
O(1 + α)
3
O(log n)
4
O(α²)
Question 13
In open-address hashing using linear probing, what issue is most responsible for performance degradation as load factor increases?
1
Coalesced chaining
2
Double hashing
3
Secondary clustering
4
Primary clustering
Question 14
Which of the following is not a desirable property of a good hash function?
1
Easy to compute
2
Minimizes collisions
3
Produces sequential contiguous values for similar keys
4
Distributes keys uniformly
Question 15
Given a hash table of size 7 and keys inserted: {9, 4, 17, 24} using h(k) = k mod 7 and linear probing for collisions, what is the resulting slot index of key 24?
1
5
2
6
3
4
4
3
Question 16
What is the load factor α of a hash table and why is it important?
1
α = m/n, it measures table size ratio to number of keys
2
α = number of collisions divided by m
3
α = n×m, it measures overall memory usage
4
α = n/m, it measures number of keys per slot and influences performance
Question 17
What is the best hashing function characteristic for a HashMap?
1
It should minimize collisions and distribute keys uniformly.
2
It should always return the same value.
3
It should work only for numbers.
4
It should generate the same hash for similar values.
Question 18
What is the impact of using a poor hash function in a HashMap?
1
The HashMap will throw an exception
2
More collisions, leading to performance degradation
3
Increased memory consumption
4
Faster lookup times
Question 19
What is the recommended load factor for optimal performance in a Java HashMap?
1
0.75
2
0.9
3
1
4
0.7
Question 20
What happens if two different keys have the same hash code in a HashMap?
1
The second key-value pair replaces the first.
2
The keys are ignored.
3
The HashMap throws an exception.
4
Both key-value pairs are stored in the same bucket using chaining or tree-based storage.
Question 21
Which of the following statements is true about Java HashMap’s key lookup process?
1
The key lookup is always O(1).
2
HashMap uses a binary search algorithm for lookups.
3
HashMap sorts keys before performing lookup.
4
HashMap checks hashCode() first, then uses equals() to confirm key identity.
Question 22
What is the main advantage of using a perfect hash function?
1
It automatically resizes the HashMap.
2
It reduces memory usage significantly.
3
It allows duplicate keys in HashMap.
4
It ensures no collisions occur.
Question 23
Which technique is used in distributed key-value stores to distribute keys across multiple nodes efficiently?
1
Chaining
2
Hash Code Modulo
3
Consistent Hashing
4
Bloom Filters
Question 24
What is "load factor" in a hash table?
1
The time taken to insert an element
2
The percentage of non-empty slots in a hash table
3
The ratio of occupied slots to the total capacity
4
The maximum number of elements allowed in a hash table
Question 25
Which technique is used to distribute keys across nodes in distributed key-value stores?
1
Binary Search
2
Bloom Filters
3
Chaining
4
Consistent Hashing