DSA & Code Snippets

Which one of the following is an application of Stack Data Structure?

• Managing function calls

• The stock span problem

• Arithmetic expression evaluation

• All of the above

Answer explanation

Arithmatic expression evaluation - Prefix, Infix, Postfix

Stock span problem can be solved using stack

Which of the following represents the Postorder Traversal of a Binary Tree?

• Left -> Right -> Root

• Left -> Root -> Right

• Right -> Left -> Root

• Right -> Root -> Left

Answer explanation

Preorder : 1 2 4 5 8 3 6 9 7

Inorder : 4 2 8 5 1 6 9 3 7

Which of the following is a linear data structure?

• Array

• AVL Trees

• Binary Trees

• Graphs

Answer explanation

Refer the Image for Classification of Data Structures

When a pop() operation is called on an empty queue, what is the condition called?

• Overflow

• Underflow

• Syntax Error

• Garbage Value

Answer explanation

Underflow -> popping out an element from empty stack

Overflow -> pushing an element into full stack

Which of the following is a Divide and Conquer algorithm?

• Bubble Sort

• Selection Sort

• Heap Sort

• Merge Sort

Answer explanation

Which of the following algorithms are used to find the shortest path from a source node to all other nodes in a weighted graph?

• BFS - Best First Search

• Djikstra’s Algorithm

• Prims Algorithm

• Kruskal’s Algorithm

Answer explanation

Dijkstra’s algorithm finds the shortest path, but Prim’s algorithm finds the MST

Which data structure is mainly used for implementing the recursive algorithm?

• Queue

• Stack

• Array

• List

Answer explanation

Stack is mainly used in recursion for implementing recursive function calls

What will be the output of the following code snippet?

• 4

• 6

• 5

• 3

Answer explanation

The code snippet basically uses binary search to calculate the floor of the square root of a number. Since the square root is an increasing function, so binary search is applicable here. Here, for n = 24, the answer is 4.

Find the output of the following program

• -127

• 127

• 2

• 129

Answer explanation

Range of byte data in java is -128 to 127. But the byte data type in java is cyclic in nature

Find the output for the given code

• -126

• Run Time Error

• 126

• Garbage Value

Answer explanation

Here the integer variable 'a' is casted into a character pointer

The character limit is from -128 to 127

when we say 130 should be casted to character, so it becomes -126.

128 becomes -128

129 becomes -127

130 becomes -126