2021-07-22 (day4)

20. Valid Parentheses

Easy

Description

Given a string s 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.

Examples

Example 1:

Input: s = "()"
Output: true

Example 2:

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

Example 3:

Input: s = "(]"
Output: false

###　Example 4:

Input: s = "([)]"
Output: false

###　Example 5:

Input: s = "{[]}"
Output: true

Constraints:

• 1 <= s.length <= 1000
• s consists of parentheses only '()[]{}'

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original question