Hash Maps / Sets Quiz

Test your understanding of hash maps and sets, including concepts like lookups, frequency counting, and deduplication. This beginner-friendly quiz is designed to reinforce key principles of efficient data structure usage for search and data management tasks.

1. Hash Map Lookup

   What is the typical time complexity of looking up a value in a hash map?

   1. O(n^2)
   2. O(1)
   3. O(log n)
   4. O(n)

2. Purpose of Sets

   Why would you use a set instead of a list when working with a large collection of items?

   1. To sort items automatically
   2. To store values with associated keys
   3. To ensure each item appears only once
   4. To maintain the insertion order

3. Counting Frequencies

   Given a list of numbers, which data structure is best for counting how many times each number appears?

   1. Stack
   2. Hash map
   3. Queue
   4. Array

4. Value Existence Check

   How can you check if the integer 42 exists in a set of numbers?

   1. Use the 'in' operator with the set
   2. Iterate with a for loop over the set
   3. Enqueue and dequeue the set
   4. Sort the set and use binary search

5. Deduplication Process

   Which method quickly removes duplicates from a list of words?

   1. Reverse the list
   2. Merge the list with itself
   3. Convert the list to a set
   4. Double each element's value

6. Key Uniqueness

   In a hash map storing city names as keys, what happens if you add the same city name twice with different values?

   1. It stores a tuple of both values
   2. An error occurs
   3. Both values are associated in a list
   4. The latest value replaces the previous one

7. Hash Function Role

   What is the primary purpose of a hash function in a hash map?

   1. To count frequency of elements
   2. To encrypt the data for privacy
   3. To map keys to locations in the underlying array
   4. To reverse the order of keys

8. Set Operations

   Which operation will show you elements that appear in both set A and set B?

   1. Padding
   2. Intersection
   3. Union
   4. Difference

9. Empty Data Structures

   Which syntax creates an empty hash map in most programming languages?

   1. Using angle brackets: u003Cu003E
   2. Using parentheses: ()
   3. Using curly braces: {}
   4. Using a single colon: :

10. Use Case Selection

    Which situation best matches a use case for a hash map?

    1. Storing and accessing student grades by their names
    2. Maintaining values in sorted order
    3. Performing calculations on adjacent numbers
    4. Processing values in a first-in, first-out order