Dharma Placement Paper - Data Structure Questions And Answers

Dharma Previous Years Solved Sample Placement Papers

1. Postfix Expression is (6*(3-(2+4))) which results -18 as output. What is the maximum number of symbols that will appear on the stack at one time during the conversion of this infix expression?
   (a) 1
   (b) 2
   (c) 3
   (d) 4
   Answer: (d)
   Explanation: During the conversion process, symbols such as +, *, (, * are placed inside the stack. At one point, a maximum of 4 symbols are stored.

2. The postfix form of the expression (A+ B)*(C*D- E)*F / G is?
   (a) AB+ CD*E – FG /**
   (b) AB + CD* E – F **G /
   (c) AB + CD* E – *F *G /
   (d) AB + CDE * – * F *G /
   Answer: (c)
   Explanation: (((A+ B)*(C*D- E)*F) / G) converts to postfix as AB+CD*E-*F*G/.

3. The data structure required to check whether an expression contains a balanced parenthesis is?
   (a) Stack
   (b) Queue
   (c) Array
   (d) Tree
   Answer: (a)
   Explanation: The stack is used to store open parentheses and match them with closed ones. If the stack is empty at the end, the parenthesis is balanced.

4. What data structure would you most likely see in a non-recursive implementation of a recursive algorithm?
   (a) Linked List
   (b) Stack
   (c) Queue
   (d) Tree
   Answer: (b)
   Explanation: Recursive algorithms use a stack to store variables and return addresses during function calls.

5. The process of accessing data stored in a serial access memory is similar to manipulating data on a?
   (a) Heap
   (b) Binary Tree
   (c) Array
   (d) Stack
   Answer: (d)
   Explanation: Serial access memory operates on a last-in, first-out principle, similar to how stacks work.

6. The postfix form of A*B+C/D is?
   (a) *AB/CD+
   (b) AB*CD/+
   (c) A*BC+/D
   (d) ABCD+/*
   Answer: (b)
   Explanation: Infix expression (A*B)+(C/D) converts to AB*CD/+ in postfix notation.

7. Which data structure is needed to convert infix notation to postfix notation?
   (a) Branch
   (b) Tree
   (c) Queue
   (d) Stack
   Answer: (d)
   Explanation: Stacks are used to manage operator precedence and reverse their order for postfix notation.

8. The prefix form of A-B/ (C * D ^ E) is?
   (a) -/*^ACBDE
   (b) -ABCD*^DE
   (c) -A/B*C^DE
   (d) -A/BC*^DE
   Answer: (c)
   Explanation: The infix expression (A-B)/(C*D^E) converts to prefix as -A/B*C^DE.

9. What is the result of the following operation? Top (Push (S, X))
   (a) X
   (b) X+S
   (c) S
   (d) XS
   Answer: (a)
   Explanation: After pushing X onto the stack, the Top operation retrieves the top element, which is X.