# Minimum Add to Make Parentheses Valid in Python

PythonServer Side ProgrammingProgramming

Suppose we have a string S of '(' and ')' parentheses, we add the minimum number of parentheses at any positions, so that the resulting parentheses string is valid. A parentheses string is valid if and only if −

• It is the empty string
• It can be written as XY (X concatenated with Y), where X and Y are valid strings
• It can be written as (A), where A is a valid string.

So if the string is like "()))((", then we need to add 4 more parentheses to make the string valid.

To solve this, we will follow these steps −

• if S is empty, then return 0
• count := 0, temp is an array, temp_counter := 0
• for i in S
• if i is opening parentheses, then insert i into temp
• otherwise
• when length of temp > 0 and last element of is opening parentheses, then delete the last element of temp, otherwise insert i into temp
• return the size of temp.

Let us see the following implementation to get better understanding −

## Example

Live Demo

class Solution:
if not S:
return 0
count = 0
temp = []
temp_counter = 0
for i in S:
if i =='(':
temp.append(i)
else:
if len(temp)>0 and temp[len(temp)-1] =='(':
temp.pop(len(temp)-1)
else:
temp.append(i)
return len(temp)
ob = Solution()
print(ob.minAddToMakeValid("()))(("))

## Input

"()))(("

## Output

4
Updated on 30-Apr-2020 07:38:19