Problem statement
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
Cases:
()( -> Not Valid
() -> Valid
([]) -> Valid
( ->Not Valid
Input
1 <= s.length <= 10^4
s consists of parentheses only '()[]{}'.
Output
print true if the string is valid, otherwise print false.