Grind75 - 20. Valid Parentheses 파이썬

20. Valid Parentheses

Easy

---

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

An input string is valid if:

1. Open brackets must be closed by the same type of brackets.
2. Open brackets must be closed in the correct order.
3. Every close bracket has a corresponding open bracket of the same type.

 

Example 1:

Input: s = "()"

Output: true

Example 2:

Input: s = "()[]{}"

Output: true

Example 3:

Input: s = "(]"

Output: false

Example 4:

Input: s = "([])"

Output: true

 

Constraints:

• 1 <= s.length <= 104
• s consists of parentheses only '()[]{}'.

 

나의 코드

class Solution:
    def isValid(self, s: str) -> bool:
        stack = []
        mapping = {')': '(', '}': '{', ']': '['}

        for c in s:
            if c in mapping:
                if not stack or stack[-1] != mapping[c]:
                    return False
                stack.pop()
            else:
                stack.append(c)

        return not stack