Python括号序列-代码优化

用字典简化代码量

class Solution:
    def isValid(self , s ):
        k = {'}':'{', ')':'(', ']':'[' }
        stack = []
        for a in s:
            if a in k.values():
                stack.append(a)
            elif not stack or k[a] != stack.pop():
                return False
        return len(stack) == 0