Practice array Quizzes

Explore array in depth with quizzes covering fundamentals to advanced concepts. DevBrainiac's structured quiz format helps you understand theory, apply logic and master problem-solving techniques. With continuous practice, you can track progress, fix mistakes and build strong command of array.

Explore All array Quizzes

Learn array step by step with interactive quizzes designed for beginners and learners revising key concepts. Build a strong foundation with clear, structured practice in array.

Question 1

What is the time complexity to access an element in an array by index?

O(log n)

O(n log n)

O(1)

O(n)

Question 2

What is the worst-case time complexity of searching for an element in an unsorted array?

O(1)

O(n log n)

O(n)

O(log n)

Question 3

Which of the following is an advantage of using an array over a linked list?

Faster access time

Uses less memory for large datasets

Dynamic size

Easier insertion and deletion

Question 4

What is the time complexity of inserting an element at the beginning of an array?

O(log n)

O( n log n)

O(1)

O(n)

Question 5

Which of the following operations is the most efficient in a circular array?

Reversing the array

Inserting at the end

Searching for an element

Deleting from the front

Question 6

In which case is a dynamic array preferred over a static array?

When searching is the primary operation

When memory usage is fixed

When frequent insertions and deletions are needed

When the array contains only unique elements

Question 7

Which data structure is best suited for implementing a stack using an array?

Binary Tree

Circular Queue

Dynamic Array

Linked List

Question 8

What is the correct way to declare an array of 10 integers in C++?

int arr[10];

array int arr[10];

int arr(10);

int arr = new int[10];

Question 9

Which of the following correctly declares an array in C++?

array{10};

int array[10];

int array;

array array[10];

Question 10

What will be the output of the following C++ code?

#include <stdio.h>
#include<iostream>
using namespace std;

int main ()
{
    int array[] = {0, 12, 4, 6, 10, 5, 3, 5};
    int n, result = 0;
    for (n = 0; n < 8; n++)
    {
        result += array[n];
    }
    cout << result;
    return 0;
}

Question 11

What will be the output of the following C++ code?

#include <stdio.h>
#include<iostream>
using namespace std;

int main ()
{
    int arr[] = {0, 12, 4, 6, 10, 5, 3, 5};
    int n, result = 0;
    for (n = 0; n < 8; n++)
    {
        result += arr[n%4];
    }
    cout << result;
    return 0;
}

Question 12

What will be the output of the following C++ code?

#include <stdio.h>
#include<iostream>
using namespace std;

int main ()
{
    int arr[] = {0, 12, 4, 6, 10, 5, 3, 5};
    int result = 0;
    for (int n = 0; n < 8; n++)
    {
        result += (arr[n%4] > 1);
    }
    cout << result;
    return 0;
}

Question 13

What will be the output of the following C++ code?

#include <stdio.h>
#include<iostream>
using namespace std;

int main ()
{
    int arr[] = {0, 12, 4, 6, 10, 5, 3, 5};
    int result = 0;
    for (int n = 0; n < 8; n++)
    {
        result += (arr[n%4] >> 1);
    }
    cout << result;
    return 0;
}

Question 14

What will be the output of the following LINQ query?

var numbers = new List<int> { 2, 3, 4, 5 };
var result = numbers.Where(n => n % 2 == 0);
Console.WriteLine(result.Count());

Question 15

What will be the output of the following code? python Copy Edit

a = [1, 2, 3, 4]
print(a[-1])

Question 16

Which method is used to remove the last element from a list?

discard()

delete()

remove()

pop()

Question 17

What will be the output of the following code?

def foo(x, y=[]):
    y.append(x)
    return y
print(foo(1))
print(foo(2))

[1, 2] [1, 2]

[1] [2]

[1] [1, 2]

[2] [2]

Question 18

What will be the output of the following code?

let a = [1, 2, 3];
let b = a;
b.push(4);
console.log(a);

ReferenceError

[1, 2, 3, 4]

TypeError

[1, 2, 3]

Question 19

Which of the following sorting algorithms works best on a nearly sorted array?

Bubble Sort

Quick Sort

Selection Sort

Insertion Sort

Question 20

What is the time complexity of merging two sorted arrays of sizes m and n?

O(log(m + n))

O(m * n)

O(m + n)

O(1)

Question 21

What is the space complexity of the merge sort algorithm for sorting an array?

O(n)

O(n log n)

O(log n)

O(1)

Question 22

In which case does the time complexity of Quick Sort become O(n²)?

When the pivot is chosen randomly

When the array contains duplicate values

When the pivot is always the median

When the array is already sorted and the first or last element is chosen as the pivot

Question 23

How do you find the largest element in an array efficiently?

Use a binary search approach

Sort the array and return the last element

Use a linear scan to find the maximum

Use recursion without extra space

Question 24

What is the time complexity of finding an element in a sorted array using binary search?

O(log n)

O(1)

O( n log n)

O(n)

Question 25

Which sorting algorithm works best for small datasets and is easy to implement?

Bubble Sort

Merge Sort

Quick Sort

Insertion Sort

Question 26

How can you efficiently find the missing number in an array of size n containing numbers from 1 to n+1?

Calculate the sum and subtract from expected sum

Use a hash set to store elements

Sort and search for the missing number

Use a linked list

Question 27

How do you efficiently check if an array contains a duplicate in O(n) time complexity?

Sort and check adjacent elements

Use a binary search

Use a hash set

Use a nested loop

Question 28

Which of the following is a disadvantage of linked lists over arrays?

More memory usage

Ease of insertion and deletion

Dynamic size

No memory wastage

Question 29

What is the time complexity of inserting an element at the head of a singly linked list?

O(n)

O(n log n)

O(1)

O(log n)

Question 30

In C++, which of the following correctly initializes a char array?

char arr[5] = "Hello";

char arr[] = "Hello";

char arr[] = {'H', 'e', 'l', 'l', 'o'};

Both 2 and 3