Leetcode Algorithm: Problem 20 & 22 (Totally different)

Problem 20. 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.
Input: s = "()"
Output: true
Input: s = "()[]{}"…