regular expression的两个问题,急啊~

Posted 2023-02-16

regular expression

1.give a regular expression defining the set of all string over a,b that do not contain the substring ab.

2.give a regular expression defining the set of all strings overa,b,cthat contain exactly two occurrences of c.
请用写这种形式的答案，谢谢了~
For example，a regular expression is constructed to represent the set of strings overab that do not contain the substring aa.
Answer:b*(ab+)*∪b*(ab+)*a

1.Answer:b*a*
2.Answer:(a|b)*c(a|b)*c(a|b)* 参考技术A 不懂 参考技术B 1 /[ab](?!ab)/

2 /[abc](.+?)c/ 参考技术C 1.give正则表达式定义的所有字符串超过（甲，乙） ，但不包含子抗体。

2.give正则表达式定义的所有字符串超过（甲，乙，丙）到底包含两个发生角 参考技术D 正则表达式，忘了