Program to check whether parentheses are balanced or not in Python

Suppose we have a string s consisting of parenthesis "(" and ")". We have to check whether the parentheses are balanced or not.

So, if the input is like s = "(()())(())", then the output will be True

To solve this, we will follow these steps −

• num_open := 0
• for each character c in s, do
  • if c is same as ')', then
    • if num_open < 0, then
      • num_open := num_open - 1
    • otherwise,
      • return False
    • otherwise,
      • num_open := num_open + 1
• return inverse of num_open

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, s):
      num_open = 0
      for c in s:
         if c == ')':
            if num_open < 0:
               num_open -= 1
            else:
               return False
            else:
               num_open += 1
      return not num_open
ob = Solution()
print(ob.solve("(()())(())"))

Input

"(()())(())"

Output

False