Program to check the balance of parenthesis in Python

January 14, 2021

Balanced Parenthesis

To check balanced parenthesis is a basic interview question where we are asked to find whether the given string(of brackets) is balanced or not. To do this , the traditional way of doing is using stacks but we can also find by using normal programming techniques. Different brackets are ( ) , [ ] , { }. Question can be asked on any type of bracket or of all types of brackets.

Sample input: ()(())
Sample output: True
Explanation : As given string is balanced it returns True.

Working:

Step 1: Take the input string
Step 2: Call the isbalanced function
Step 3: This function returns True if string is balanced , else False
Step 4: This function returns true or false for the string that contains ( )

Python code:

Solution 1:

def isbalanced(s):
    c= 0
    ans=False
    for i in s:
        if i == “(“:
            c += 1
        elif i == “)”:
            c-= 1
        if c < 0:
            return ans
    if c==0:
        return not ans
    return ans
s=input(“Enter a string of brackets: “) 
print(“Given string is balanced :”,isbalanced(s)) 

Enter a string of brackets: ()(())
Given string is balanced : True

Working:

This approach is to check whether the string is balanced or not in case the string contains several types of brackets like { ( [ ] ) }

Step 1: Take the input string
Step 2: Call the isbalanced function
Step 3: This function returns True if string is balanced , else False
Step 4: This function replaces the set of brackets until the string len becomes zero

Solution 2:

def isbalanced(s):
    while(len(s)!=0):
        s = s.replace(‘()’, ”) 
        s = s.replace(‘[]’, ”)
        s = s.replace(‘{}‘, ”)
    if(len(s)== 0):
        return True
    else:
        return False
s=input(“Enter a string of brackets: “) 
print(“Given string is balanced :”,isbalanced(s)) 

Enter a string of brackets: ({{}}){}[]
Given string is balanced : True

Prepinsta Prime

Prepinsta Prime

Program to check the balance of parenthesis in Python

Balanced Parenthesis

Working:

Python code:

Solution 1:

Working:

Solution 2: