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Theory of Computation · Regular Expressions and Finite Automata
Official IIT answer key · IIT Delhi · Audited Aug 2026
GATE CSE 2020 Q7 · MCQ · 1 mark
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Topic notes
The topic of Regular Expressions and Finite Automata is one of the highest-weight core areas in GATE CS Theory of Computation. Questions test minimal DFA state counting under modulo/substring constraints, state equivalence and minimization, regular expression derivation from transition graphs (and vice versa), NFA-to-DFA powerset bounds (2n), and language membership/closure properties. The distribution balances 1-mark foundational conceptual checks with 2-mark state-tracing and counting problems.
Full Regular Expressions and Finite Automata guide →All 41 questions on Regular Expressions and Finite Automata →
Which one of the following regular expressions represents the set of all binary strings with an odd number of 1's?
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