678 - Valid Parenthesis String.

Medium

Given a string s containing only three types of characters: '(', ')' and '*', return true if s is valid.

The following rules define a valid string:

• Any left parenthesis '(' must have a corresponding right parenthesis ')'.

• Any right parenthesis ')' must have a corresponding left parenthesis '('.

• Left parenthesis '(' must go before the corresponding right parenthesis ')'.

• '*' could be treated as a single right parenthesis ')' or a single left parenthesis '(' or an empty string "".

Example 1:

Input: s = "()"

Output: true

Example 2:

Input: s = "(\*)"

Output: true

Example 3:

Input: s = "(\*))"

Output: true

Constraints:

• 1 <= s.length <= 100

• s[i] is '(', ')' or '*'.