Free Practice Quiz Question List

3 Arrays and Dynamic Arrays Online Quiz Questions

Use this free practice quiz with 20 questions to review 3 Arrays and Dynamic Arrays, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

True or false: Because an array stores same-sized elements in contiguous memory, accessing an element by index can take $O(1)$ time.

A
True
B
False

Choose one

1 point

Given values = [18, 7, 25, 4], what value does values[2] return?

A
18
B
25
C
7
D
4

Written response

1 point

An array has length 8 and uses zero-based indexing. What is the index of its final element?

Fill in the blank

1 point

A traversal that visits every element of an array containing $n$ elements takes time.

Choose one

1 point

Why can inserting an element at the beginning of an array take $O(n)$ time?

A
No elements need to move, so insertion is always $O(1)$ .
B
Existing elements must shift right, so insertion can take $O(n)$ .
C
The array must be searched, so insertion is always $O(\log n)$ .
D
Only the new element is copied, so insertion is always $O(1)$ .

True or false

1 point

True or false: If order must be maintained, deleting the last element of an array takes $O(1)$ time.

A
True
B
False

Choose all

1 point

Select all properties that correctly describe a dynamic array.

A
It tracks the number of stored elements as size.
B
It tracks the number of available positions in its backing array as capacity.
C
Insertion at the beginning is always $O(1)$ .
D
Indexed access is $O(1)$ .

Written response

1 point

A dynamic array has size 3 and capacity 5. How many additional elements can it store before resizing?

Fill in the blank

1 point

In a typical dynamic-array append, when size equals capacity, the structure must first the backing array.

Choose one

1 point

Why does geometric capacity growth make repeated dynamic-array appends have amortized cost $O(1)$ ?

A
Every individual append, including a resize, takes $O(1)$ .
B
Geometric growth prevents any copying during a resize.
C
The total number of copied elements across many appends is $O(n)$ .
D
A dynamic array never allocates a new backing array.

Choose all

1 point

Select all situations for which a dynamic array is generally a strong choice.

A
Fast indexed access is a strength.
B
Efficient traversal is a strength.
C
Frequent insertion at the beginning is a strength because no shifting is needed.
D
Appending near the end is a strength.

Open ended

1 point

Explain what happens when a dynamic array is full and an append triggers resizing. Include the major resizing steps and explain why geometric growth gives append an amortized complexity of $O(1)$ , even though one resize can take $O(n)$ .

Choose one

1 point

Which capacity-reservation strategy best follows the material's practical guidance when future growth can be estimated?

A
Reserve exactly one additional position before every append.
B
Reserve capacity in meaningful batches when future growth is known or can be estimated.
C
Never reserve capacity because reservation always changes the logical size.
D
Reserve only after every append has already triggered a resize.

True or false

1 point

True or false: Shrinking a dynamic array after every deletion is a good way to avoid thrashing.

A
True
B
False

Choose one

1 point

An array has length 6. Which range contains all of its valid zero-based indices?

A
0 through 6
B
0 through 5
C
1 through 6
D
1 through 5

Choose one

1 point

Why can an array access by index usually run in $O(1)$ time?

A
The address is computed from the base address, index, and element size.
B
The array is searched from the first element until the requested one is found.
C
Every element is copied before the requested element is accessed.
D
The requested element is always stored at the same physical address for every array.

Choose one

1 point

A program visits every element of an array once and creates no additional structure proportional to the array length. What are the time and auxiliary-space complexities?

A
Time $O(1)$ , auxiliary space $O(1)$
B
Time $O(1)$ , auxiliary space $O(n)$
C
Time $O(n)$ , auxiliary space $O(1)$
D
Time $O(n)$ , auxiliary space $O(n)$

Choose one

1 point

To insert an element at an index in the middle of an ordered array, what must the implementation generally do?

A
Only the new element is written, so insertion is always $O(1)$ .
B
The array is converted into a linked structure before insertion.
C
Elements before the insertion point are shifted right.
D
Elements from the end down to the insertion point are shifted right.

Written response

1 point

A dynamic array has size 7 and capacity 8. After one successful append, what is its resulting size?

Written response

1 point

An unordered array contains n elements. To delete the element at index i in O(1) time when preserving the order of the remaining elements is unnecessary, which existing element should replace array[i] before the logical size is reduced?