[LeetCode] 921. Minimum Add to Make Parentheses Valid 使括号有效的最少添加

Given a string?S?of?‘(‘?and?‘)‘?parentheses, we add the minimum number of parentheses (?‘(‘?or?‘)‘, and in any positions ) so that the resulting parentheses string is valid.

Formally, a parentheses string is valid if and only if:

• It is the empty string, or
• 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.

Given a parentheses string, return the minimum number of parentheses we must add to make the resulting string valid.

Example 1:

Input: "())"
Output: 1

Example 2:

Input: "((("
Output: 3

Example 3:

Input: "()"
Output: 0

Example 4:

Input: "()))(("
Output: 4

Note:

1. S.length <= 1000
2. S?only consists of?‘(‘?and?‘)‘?characters.

Github 同步地址:

https://github.com/grandyang/leetcode/issues/CHANGE_ME

类似题目：

参考资料：

https://leetcode.com/problems/minimum-add-to-make-parentheses-valid/

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[LeetCode] 921. Minimum Add to Make Parentheses Valid 使括号有效的最少添加

原文：https://www.cnblogs.com/grandyang/p/11769067.html