#921
Minimum Add to Make Parentheses Valid
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Description
A parentheses string is valid if and only if:
- It is the empty string,
- It can be written as AB (A concatenated with B), where A and B are valid strings, or
- It can be written as (A), where A is a valid string.
You are given a parentheses string s. In one move, you can insert a parenthesis at any position of the string.
- For example, if s = "()))", you can insert an opening parenthesis to be "(()))" or a closing parenthesis to be "())))".
Return the minimum number of moves required to make s valid.
Example 1:
Input: s = "())"
Output: 1
Example 2:
Input: s = "((("
Output: 3
Solution