leetcode 921. 使括号有效的最少添加（Python）

 

 1 class solution:
 2     def minaddtomakevalid(self, s):
 3         """
 4         :type s: str
 5         :rtype: int
 6         """
 7         stack = []
 8         s = list(s)
 9         for s in s:
10             if len(stack) != 0:
11                 if s == ")" and stack[-1] == "(":
12                     stack.pop()
13                 else:
14                     stack.append(s)
15             else:
16                 stack.append(s)
17         return len(stack)

击败了百分之百的人，纪念一下。