In the context of hash tables, what does a high load factor indicate?
Lower memory usage.
A more efficient hash function is being used.
Faster insertion operations.
A higher probability of collisions.
What is the primary reason for using a prime number as the size of a hash table in many implementations?
To make the implementation of the hash table simpler.
To ensure an even distribution of keys across the hash table, reducing collisions.
To minimize the memory usage of the hash table.
To increase the speed of hash function computation.
Which of these data structures can provide a more secure and performant alternative to a hashmap when handling user authentication data, especially in scenarios prone to hash flooding attacks?
Queue
Array
Tree
Linked list
How can a hash flooding attack impact the performance of a web server using a hashmap to store session data?
It has no impact on performance, as hash flooding attacks only target data integrity.
It can lead to increased memory usage and faster response times.
It can improve the efficiency of the hashmap by distributing data more evenly.
It can cause a denial-of-service by forcing the server to handle a large number of collisions.
In the context of hashmaps, what is a 'universal hash function' primarily designed to protect against?
Attempts to guess the keys used in the hashmap by analyzing the distribution of hashed values.
Denial-of-service attacks caused by hash flooding.
Collisions caused by malicious input specifically crafted to exploit a known hash function.
Data corruption caused by accidental hash collisions between legitimate inputs.
In a hash table with open addressing using linear probing, suppose we perform a sequence of insertions where each key hashes to the same index. What is the time complexity of the nth insertion in the worst case?
O(n log n)
O(1)
O(log n)
O(n)
Why is it generally recommended to avoid using mutable objects as keys in hash tables?
Hash tables cannot store mutable objects as keys; only immutable objects are allowed.
Using mutable keys increases the memory overhead of the hash table.
Mutable keys can lead to inconsistent state if their values are modified after being inserted into the hash table.
Mutable keys make the implementation of the hash table significantly more complex.
What security risk arises from storing sensitive data like passwords directly in a hashmap, even when hashed?
Hash collisions could allow attackers to bypass authentication.
Storing any data in a hashmap increases the risk of SQL injection attacks.
An attacker gaining access to the hashmap could retrieve the plaintext passwords.
Hashmaps are inherently less secure than other data structures for storing passwords.
In the context of amortized analysis of hash table operations, what does the term "amortized" refer to?
The average time complexity of an operation over a sequence of operations.
The worst-case time complexity of an operation.
The best-case time complexity of an operation.
The time complexity of an operation when the hash table is full.
Hopscotch hashing aims to improve the performance of open addressing by:
Using a dynamic array to resize the table when the load factor gets high.
Limiting the maximum distance a key can be placed from its original hash index.
Employing a binary search tree for efficient collision resolution.
Using multiple hash tables to store keys with different hash values.