// Valid Parentheses — EASY

// Category: stack

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

An input string is valid if:

- Open brackets are closed by the same type of brackets.

- Open brackets are closed in the correct order.

- Every close bracket has a corresponding open bracket of the same type.

Example: s = "()"

Output: true