Validate whether brackets are properly nested

Problem Statement

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

Function Signature

def is_valid(s: str) -> bool:

Constraints

• 1 <= s.length <= 10^4
• s consists of parentheses only: ()[]{}

Examples

Example 1: Input: s = "()[]{}" Output: True

Example 2: Input: s = "([)]" Output: False

Example 3: Input: s = "{[]}" Output: True

Edge Cases

• Empty strings or strings with an odd length should be handled appropriately.
• Strings with only opening or only closing brackets.