Valid Parentheses

Valid Parentheses

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.

Examples

Example 1:

Input: s = "()"
Output: true

Example 2:

Input: s = "()[]{}"
Output: true
Explanation: All three types of brackets are properly opened and closed.

Example 3:

Input: s = "(]"
Output: false
Explanation: The opening '(' does not match the closing ']'.

Example 4:

Input: s = "([)]"
Output: false
Explanation: The brackets are not closed in the correct order.

Example 5:

Input: s = "{[]}"
Output: true
Explanation: Nested brackets are properly matched.

Constraints

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

Expected Complexity

• Time: O(n)
• Space: O(n)