[LeetCode] Valid Parenthesis String 验证括号字符串

Posted 2020-10-09 Grandyang

 

Given a string containing only three types of characters: ‘(‘, ‘)‘ and ‘*‘, write a function to check whether this string is valid. We define the validity of a string by these rules:

1. Any left parenthesis ‘(‘ must have a corresponding right parenthesis ‘)‘.
2. Any right parenthesis ‘)‘ must have a corresponding left parenthesis ‘(‘.
3. Left parenthesis ‘(‘ must go before the corresponding right parenthesis ‘)‘.
4. ‘*‘ could be treated as a single right parenthesis ‘)‘ or a single left parenthesis ‘(‘ or an empty string.
5. An empty string is also valid.

 

Example 1:

Input: "()"
Output: True

 

Example 2:

Input: "(*)"
Output: True

 

Example 3:

Input: "(*))"
Output: True

 

Note:

1. The string size will be in the range [1, 100].

 

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