Balanced Brackets

Given a string s made up exclusively of these bracket characters: '(', ')', '{', '}', '[', and ']'.

A string s counts as valid exactly when all of the following hold:

1. Each opening bracket is eventually matched with its corresponding closing bracket type.
2. Brackets must be closed in last-opened, first-closed order.
3. No closing bracket may appear without a matching opening bracket of the same kind.

Return true when s is valid; otherwise, return false.

isValid(s)

Examples

Example 1:

Input: s = "{}"

Output: true

Explanation:

The opening curly bracket is paired with the correct closing curly bracket.

Example 2:

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

Output: true

Explanation:

Each nested pair is closed by the appropriate bracket in reverse opening order.

Example 3:

Input: s = "{(]}"

Output: false

Explanation:

The ( bracket is followed by ], which is not its matching closing bracket.

Constraints

• 1 <= s.length <= 10^4
• s contains only bracket characters from ()[]{}