## DEV Community

Abhishek Chaudhary

Posted on

# Minimum Remove to Make Valid Parentheses

Given a string s of `'('` , `')'` and lowercase English characters.

Your task is to remove the minimum number of parentheses ( `'('` or `')'`, in any positions ) so that the resulting parentheses string is valid and return any valid string.

Formally, a parentheses string is valid if and only if:

• It is the empty string, contains only lowercase characters, or
• It can be written as `AB` (`A` concatenated with `B`), where `A` and `B` are valid strings, or
• It can be written as `(A)`, where `A` is a valid string.

Example 1:

Input: s = "lee(t(c)o)de)"
Output: "lee(t(c)o)de"
Explanation: "lee(t(co)de)" , "lee(t(c)ode)" would also be accepted.

Example 2:

Input: s = "a)b(c)d"
Output: "ab(c)d"

Example 3:

Input: s = "))(("
Output: ""
Explanation: An empty string is also valid.

Constraints:

• `1 <= s.length <= 105`
• `s[i]` is either`'('` , `')'`, or lowercase English letter`.`

SOLUTION:

``````class Solution:
def minRemoveToMakeValid(self, s: str) -> str:
op = set()
n = len(s)
stack = []
for i in range(n):
if s[i] == '(':
stack.append(i)