歧义和无歧义语法之间的区别

先决条件 – 上下文无关语法
1. 歧义语法：
如果存在多个派生树或解析树，则上下文无关文法称为二义性文法。

例子 –

S -> S + S / S * S / S / a 

2. 明确语法：
如果存在一棵且只有一棵派生树或解析树，则上下文无关文法称为无歧义文法。

例子 –

X -> AB
A -> Aa / a
B -> b 

歧义和无歧义语法之间的区别：

S.NO	Ambiguous Grammar	Unambiguous Grammar
1.	In ambiguous grammar, the leftmost and rightmost derivations are not same.	In unambiguous grammar, the leftmost and rightmost derivations are same.
2.	Amount of non-terminals in ambiguous grammar is less than in unambiguous grammar.	Amount of non-terminals in unambiguous grammar is more than in ambiguous grammar.
3.	Length of the parse tree in ambiguous grammar is comparatively short.	Length of the parse tree in unambiguous grammar is comparatively large.
4.	Speed of derivation of a tree in ambiguous grammar is faster than that of unambiguous grammar.	Speed of derivation of a tree in unambiguous grammar is slower than that of ambiguous grammar.
5.	Ambiguous grammar generates more than one parse tree.	Unambiguous grammar generates only one parse tree.
6.	Ambiguous grammar contains ambiguity.	Unambiguous grammar does not contain any ambiguity.