TCS NQT Guide TCS NQT Coding Capability & AlgorithmsBalanced Parentheses and Infix/Postfix/Prefix Expressions

Balanced Parentheses and Infix/Postfix/Prefix Expressions

Learn core concepts, essential formulas, and attempt practice questions designed on the latest TCS NQT testing patterns.

Key Concepts & Formulas

1Balanced Parentheses: Push open brackets onto stack; pop on matching close brackets.
2Expressions representations: Infix (A+B), Postfix (AB+), Prefix (+AB).

Practice Question 1

Convert infix expression 'A + B * C' to postfix:

A) ABC*+

B) AB+C*

C) +A*BC

D) ABC+*

Correct Answer: A) ABC*+

Step-by-step Solution: Multiplication (*) has higher precedence than addition (+). B * C becomes BC*. Then addition: A + BC* becomes ABC*+.

Practice Question 2

What is stack state after parsing '{[' in balanced check?

A) ['{', '[']

B) ['[']

C) ['}']

D) Empty

Correct Answer: A) ['{', '[']

Step-by-step Solution: Open brackets are pushed onto the stack in the order they appear. Stack: ['{', '['].

Remember that operators with higher precedence are popped from the stack first during conversions.