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