Other Array Types MCQs: 10 Solved Questions with Explanations

“Other array types” is not one definition that you can memorise and apply everywhere. Bit arrays, parallel arrays, dynamic arrays, bounded-size layouts, sparse matrices, and array-backed heaps are six different ideas, so decide what one index or one size represents before you trust an option. Dynamic-array grow and shrink thresholds are the design policy of a particular implementation rather than a universal law, so do not memorise a percentage as a rule. Separate logical size from physical capacity, then use the Data Structures MCQs hub for broader revision.

1. Other array types: the six ideas to separate before solving

First ask what one position means. It may represent a bit, one field index shared across arrays, or a heap node related to other indices.

Logical size counts visible elements, while physical size or capacity counts all allocated backing slots, including unused ones. Revise Arrays in C: Declaration, Initialization and Worked Examples if the ordinary contiguous-array baseline is unclear.

2. Bit arrays, binary arrays and sparse matrices: Questions 1, 4 and 10

Question 1

Accenture 2025

Open Question 1 in the question bank.

What is a bit array?

• A. Data structure for representing arrays of records

• B. Data structure that compactly stores bits

• C. An array in which most of the elements have the same value

• D. Array in which elements are not present in continuous locations

Correct answer: B.

A bit array compactly stores bit-valued or Boolean states, as in [1, 0, 1, 1, 0, 0, 1, 0]. A describes record storage, C points towards repeated-value data, and D conflicts with normal array contiguity.

Question 4

UP Police 2016

Open Question 4 in the question bank.

The number of different binary arrays of order n x n, where each cell stores either 0 or 1, is:

• A. 2^(2n)

• B. 2^(n^2)

• C. n^2

• D. 2^n

Correct answer: B.

An n x n array has n^2 independent cells, and each cell has two choices. The multiplication rule therefore gives 2^(n^2) possible arrays. For n = 2, four cells produce 2^4 = 16 arrays, confirming the exponent.

Question 10

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Open Question 10 in the question bank.

Which of the following is the most suitable reason for using a sparse matrix representation instead of a traditional 2D array?

• A. It allows dynamic resizing of the matrix.

• B. It simplifies matrix multiplication logic.

• C. It reduces memory usage when most elements are zero.

• D. It improves cache performance in matrix traversal.

Correct answer: C.

A dense 1000 x 1000 matrix reserves 1,000,000 value positions. For 5,000 non-zero values, simple row-column-value triplets use 5,000 x 3 = 15,000 scalar fields. In this simplified field-count comparison, 15,000 / 1,000,000 x 100 = 1.5%, so space is the primary reason; the other behaviours depend on the sparse format.

3. Parallel arrays: Questions 2 and 9

Question 2

AMCAT 2025

Open Question 2 in the question bank.

Which of the following can be called a parallel array implementation?

A.

firstName = ['Joe','Bob','Frank','Hans']
lastName = ['Smith','Seger','Sinatra','Schultze']
heightInCM = [169,158,201,199]
for i in xrange(len(firstName)):
    print "Name:",firstName[i], lastName[i]
    print "Height in CM:", heightInCM[i]

B.

firstName = ['Joe','Bob','Frank','Hans']
lastName = ['Smith','Seger']
heightInCM = [169,158]
for i in xrange(len(firstName)):
    print "Name:",firstName[i], lastName[i]
    print "Height in CM:", heightInCM[i]

C.

firstName = ['Joe','Bob']
lastName = ['Smith','Seger','Sinatra','Schultze']
heightInCM = [169,158]
for i in xrange(len(firstName)):
    print "Name:",firstName[i], lastName[i]
    print "Height in CM:", heightInCM[i]

D.

firstName = ['Joe','Bob']
lastName = ['Smith','Seger' ,'Schultze']
heightInCM = [169,158]
for i in xrange(len(firstName)):
    print "Name:",firstName[i], lastName[i]
    print "Height in CM:", heightInCM[i]

Correct answer: A.

The lengths are 4, 4, 4 in A, 4, 2, 2 in B, 2, 4, 2 in C, and 2, 3, 2 in D. Only A stays aligned, so index 2 combines Frank, Sinatra, and 201 without an out-of-range access.

Question 9

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Open Question 9 in the question bank.

Which of the following is a disadvantage of parallel array over the traditional arrays?

• A. When a language does not support records, parallel arrays can be used

• B. Increased locality of reference

• C. Ideal cache behaviour

• D. Insertion and Deletion becomes tedious

Correct answer: D.

Insertion or deletion requires coordinated changes to the first-name, last-name, and height arrays while preserving alignment. A is a use case, while B and C can be advantages for suitable access patterns.

4. Dynamic-array size, capacity and insertion: Questions 3, 5 and 7

Question 3

BPSC 2024

Open Question 3 in the question bank.

What is the time complexity of inserting at the end in dynamic arrays?

• A. O(1)

• B. O(n)

• C. Either O(1) or O(n)

• D. More than one of the above

• E. None of the above

Correct answer: C.

An append takes O(1) when unused capacity remains. If the backing array is full, allocating a larger array and copying n elements makes that append O(n); across a long sequence, the amortized cost is O(1). The question asks for the per-operation possibilities, so C is the most complete option.

Question 5

Goldman Sachs 2024

Open Question 5 in the question bank.

The size of the dynamic array is deallocated if the array size is less than _________% of the backend physical size.

• A. 30

• B. 40

• C. 10

• D. 20

Correct answer: A.

This question assumes a 30% shrinking policy, not a universal runtime standard. At size 29 and capacity 100, 29 / 100 x 100 = 29%, so the stated policy triggers. At size 30, the result is exactly 30%, which is not less than 30%.

Question 7

TCS 2024

Open Question 7 in the question bank.

What is meant by physical size in a dynamic array?

• A. The size allocated to elements

• B. The size extended to add new elements

• C. The size of the underlying array at the back-end

• D. The size visible to users

Correct answer: C.

Physical size is backing-array capacity. With five visible elements and capacity eight, logical size is 5, physical size is 8, and 8 - 5 = 3 slots remain. D describes logical size.

5. Bounded-size arrays and heap indexing: Questions 6 and 8

Question 6

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Open Question 6 in the question bank.

Array is divided into two parts in ____________

• A. Hashed Array Tree

• B. Geometric Array

• C. Bounded-size dynamic array

• D. Sparse Array

Correct answer: C.

At capacity 8, occupied indices 0..4 form one region and reserve indices 5..7 form the other, a five-element and three-position split inside a single array. That is what C describes. A hashed array tree also has structure, but it spreads elements across many fixed-size leaf arrays reached through a top-level directory, so it is not one array cut into two parts. A geometric array names a growth pattern only, and a sparse array is about which entries get stored at all.

Question 8

GATE 2001

Open Question 8 in the question bank.

Consider a 1-based array representation of an n-element binary heap, where elements are stored from index 1 to index n. For a non-root element stored at index i (1 < i <= n), the index of its parent is:

• A. i - 1

• B. floor(i/2)

• C. ceiling(i/2)

• D. (i + 1)/2

Correct answer: B.

In a 1-based heap, the children of parent p are at 2p and 2p + 1, so reversing the relation gives parent floor(i/2) for i > 1; the root at index 1 has no parent. For even index 8, floor(8/2) = 4; for odd index 9, floor(9/2) = floor(4.5) = 4. This question also appears in the earlier Heaps and Priority Queues MCQs set, where it anchors heap-array basics. Here it tests whether you can pick the 1-based index rule from a mixed set of array representations.

6. Other array types: a three-check method for timed MCQs

Use this routine before reading the options:

1. Identify the index meaning. Parallel arrays at index 2 produce (Frank, Sinatra, 201).

2. Separate size from capacity. Size 29 against capacity 100 gives 29%, below the assumed 30% threshold.

3. Distinguish saving space from reorganising data. Sparse storage saves space when zeros dominate; parallel arrays reorganise fields.

Reject four common traps: unequal parallel-array lengths, a resize threshold treated as universal, sparse confused with non-contiguous, and a parent index taken as ceiling(i/2). That returns 5 for index 9, while the correct parent is 4. In a 1-based heap, indices 8 and 9 both have parent 4.

7. How other array types MCQs are tested, and what to practise next

Question 1 checks a definition; Questions 2, 6, and 9 check layout and coordination; Questions 3, 5, and 7 check capacity and append behaviour; and Questions 4, 8, and 10 use representation arithmetic or memory choice. Re-solve the set without options, then explain every rejected choice.

Use the Coding & DSA category to choose your next topic. For a wider placement-coding path, use Coding for Placements. For the next revision pass, use the ten linked pages and Data Structures MCQs hub.