DSA Quiz

How is the 2nd element in an array accessed based on pointer notation?

• *a + 2

• *(a + 2)

• *(*a + 2)

• &(a + 2)

Which of the following is example of in-place algorithm?

• Bubble Sort

• Merge Sort

• Insertion Sort

• All of the above

The data structure required to check whether an expression contains a balanced parenthesis is?

• Stack

• Queue

• Array

• All of the above

Answer explanation

Explanation: The stack is a simple data structure in which elements are added and removed based on the LIFO principle. Open parenthesis is pushed into the stack and a closed parenthesis pops out elements till the top element of the stack is its corresponding open parenthesis. If the stack is empty, parenthesis is balanced otherwise it is unbalanced

When does the ArrayIndexOutOfBoundsException occur?

• Compile-time

• Run-time

• Not an error

• Not an exception at all

Answer explanation

Explanation: ArrayIndexOutOfBoundsException is a run-time exception and the compilation is error-free.

What is the speciality about the inorder traversal of a binary search tree?

• It traverses in a non increasing order

• It traverses in an increasing order

• It traverses in a random fashion

• It traverses based on priority of the node

Answer explanation

Explanation: As a binary search tree consists of elements lesser than the node to the left and the ones greater than the node to the right, an inorder traversal will give the elements in an increasing order.

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

• O(1)

• O(n)

• O(logn)

• Either O(1) or O(n)

Answer explanation

Explanation: Depending on whether the array is full or not, the complexity in dynamic array varies. If you try to insert into an array that is not full, then the element is simply stored at the end, this takes O(1) time. If you try to insert into an array which is full, first you will have to allocate an array with double the size of the current array and then copy all the elements into it and finally insert the new element, this takes O(n) time.

5.

The following formula will produce

Fn = Fn-1 + Fn-2

• Armstrong Number

• Fibonacci Series

• Euler Number

• Prime Number

What is the output of the following code snippet?

void solve() {

stack<int> s;

s.push(1);

s.push(2);

s.push(3);

for(int i = 1; i <= 3; i++) {

cout << s.top() << “ “;

s.pop();

}

}

• 3 2 1

• 1 2 3

• 3

• 1

A priority queue can efficiently implemented using which of the following data structures? Assume that the number of insert and peek (operation to see the current highest priority item) and extraction (remove the highest priority item) operations are almost same.

• Linked List

• Array

• Heap Data Structures like Binary Heap, Fibonacci Heap

• None of the Above

Which of the following is a true about Binary Trees

• Every binary tree is either complete or full.

• Every complete binary tree is also a full binary tree.

• Every full binary tree is also a complete binary tree.

• No binary tree is both complete and full.

• None of the Above