: [ S \to aSa \mid bSb \mid a \mid b \mid \varepsilon ]

: [ S \to aSbS \mid bSaS \mid \varepsilon ]

Check: ( S \Rightarrow aA \Rightarrow abS \Rightarrow ab\varepsilon = ab ) (length 2). Works. Language : All strings of ( and ) that are balanced.

: [ S \to aS \mid bS \mid \varepsilon ] Wait — that gives any length. Let's fix:

S → aSbb → a(aSbb)bb → aa(ε)bbbb → aabbbb (wrong). So that’s 4 b’s, not 3.

Cfg Solved Examples «2026 Edition»

: [ S \to aSa \mid bSb \mid a \mid b \mid \varepsilon ]

: [ S \to aSbS \mid bSaS \mid \varepsilon ] cfg solved examples

Check: ( S \Rightarrow aA \Rightarrow abS \Rightarrow ab\varepsilon = ab ) (length 2). Works. Language : All strings of ( and ) that are balanced. : [ S \to aSa \mid bSb \mid

: [ S \to aS \mid bS \mid \varepsilon ] Wait — that gives any length. Let's fix: cfg solved examples

S → aSbb → a(aSbb)bb → aa(ε)bbbb → aabbbb (wrong). So that’s 4 b’s, not 3.