LeetCode 20. Valid Parentheses--笔试题--Python解法

题目地址：Valid Parentheses - LeetCode

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Given a string containing just the characters ‘(’, ‘)’, ‘{’, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.

An input string is valid if:

Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.
Note that an empty string is also considered valid.

Example 1:

Input: "()"
Output: true

Example 2:

Input: "()[]{}"
Output: true

Example 3:

Input: "(]"
Output: false

Example 4:

Input: "([)]"
Output: false

Example 5:

Input: "{[]}"
Output: true

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忘了这是那家公司的笔试题。
题目看起来并不难。

Python解法如下：

class Solution:
    def isValid(self, s: str