Gate CS-2015-2 Question Paper With Solutions

Q. 47 Which of the following languages is/are regular?

L1: {wxwR ⎪ w, x ∈ {a, b}* and ⎪w⎪, ⎪x⎪ >0} wR is the reverse of string w
L2: {anbm ⎪m ≠ n and m, n≥0
L3: {apbqcr ⎪ p, q, r ≥ 0}

(A) L1 and L3 only

(B) L2 only

(C) L2 and L3 only

(D) L3 only

Answer: (A)

Explanation: