Day 2 - Valid Parentheses

Open brackets must be closed by the same type of brackets.Open brackets must be closed in the correct order.

class Solution:    def isValid(self, s: str) -> bool:        stack =[]        for i in s:             if i == "(" or i == "{" or i == "[" :                 stack.append(i)            elif i == ")" :                 if stack and stack[-1]=="(":                      stack.pop()                else:                     stack.append(i)            elif i == "}" :                 if stack and stack[-1]=="{":                     stack.pop()                else:                     stack.append(i)            elif i == "]" :                 if stack and stack[-1]=="[":                     stack.pop()                else:                     stack.append(i)        if stack:            return False         else:             return True