Given a string representing a code snippet, implement a tag validator to parse the code and return whether it is valid.
A code snippet is valid if all the following rules hold:
Examples
Example 1
Input: code = "<DIV>This is the first line <![CDATA[<div>]]></DIV>"
Output: true
Explanation:
The code is wrapped in a closed tag : <DIV> and </DIV>.
The TAG_NAME is valid, the TAG_CONTENT consists of some characters and cdata.
Although CDATA_CONTENT has an unmatched start tag with invalid TAG_NAME, it should be considered as plain text, not parsed as a tag.
So TAG_CONTENT is valid, and then the code is valid. Thus return true.
Example 2
Input: code = "<DIV>>> ![cdata[]] <![CDATA[<div>]>]]>]]>>]</DIV>"
Output: true
Explanation:
We first separate the code into : start_tag|tag_content|end_tag.
start_tag -> "<DIV>"
end_tag -> "</DIV>"
tag_content could also be separated into : text1|cdata|text2.
text1 -> ">> ![cdata[]] "
cdata -> "<![CDATA[<div>]>]]>", where the CDATA_CONTENT is "<div>]>"
text2 -> "]]>>]"
The reason why start_tag is NOT "<DIV>>>" is because of the rule 6.
The reason why cdata is NOT "<![CDATA[<div>]>]]>]]>" is because of the rule 7.
Example 3
Input: code = "<A> <B> </A> </B>"
Output: false
Explanation: Unbalanced. If "<A>" is closed, then "<B>" must be unmatched, and vice versa.
Constraints
1 <= code.length <= 500
code consists of English letters, digits, '<', '>', '/', '!', '[', ']', '.', and ' '.
591. Tag Validator
Hard
50 Points
String
Stack
Given a string representing a code snippet, implement a tag validator to parse the code and return whether it is valid.
A code snippet is valid if all the following rules hold:
Examples
Example 1
Input: code = "<DIV>This is the first line <![CDATA[<div>]]></DIV>"
Output: true
Explanation:
The code is wrapped in a closed tag : <DIV> and </DIV>.
The TAG_NAME is valid, the TAG_CONTENT consists of some characters and cdata.
Although CDATA_CONTENT has an unmatched start tag with invalid TAG_NAME, it should be considered as plain text, not parsed as a tag.
So TAG_CONTENT is valid, and then the code is valid. Thus return true.
Example 2
Input: code = "<DIV>>> ![cdata[]] <![CDATA[<div>]>]]>]]>>]</DIV>"
Output: true
Explanation:
We first separate the code into : start_tag|tag_content|end_tag.
start_tag -> "<DIV>"
end_tag -> "</DIV>"
tag_content could also be separated into : text1|cdata|text2.
text1 -> ">> ![cdata[]] "
cdata -> "<![CDATA[<div>]>]]>", where the CDATA_CONTENT is "<div>]>"
text2 -> "]]>>]"
The reason why start_tag is NOT "<DIV>>>" is because of the rule 6.
The reason why cdata is NOT "<![CDATA[<div>]>]]>]]>" is because of the rule 7.
Example 3
Input: code = "<A> <B> </A> </B>"
Output: false
Explanation: Unbalanced. If "<A>" is closed, then "<B>" must be unmatched, and vice versa.
Constraints
1 <= code.length <= 500
code consists of English letters, digits, '<', '>', '/', '!', '[', ']', '.', and ' '.