parenthesis_balanced_checking.py

class Stack:
    def __init__(self):
        self.items = []

    def isEmpty(self):
        return self.items == []

    def push(self, item):
        self.items.append(item)

    def pop(self):
        return self.items.pop()

    def peek(self):
        return self.items[len(self.items) - 1]

    def size(self):
        return len(self.items)


def parChecker(symbolString):
    s = Stack()
    for i in symbolString:
        if i == '(' or i == '{' or i == '[':
            s.push(i)
            continue
        if s.isEmpty():
            return False
        x = s.peek()
        s.pop()
        if i == ')' and (x == '{' or x == '['):
            return False
        elif i == '}' and (x == '(' or x == '['):
            return False
        elif i == ']' and (x == '(' or x == '{'):
            return False
    return s.isEmpty()


# from pythonds.basic.stack import Stack
#
#
# def parChecker(symbolString):
#     s = Stack()
#     balanced = True
#     index = 0
#     while index < len(symbolString) and balanced:
#         symbol = symbolString[index]
#         if symbol == "(":
#             s.push(symbol)
#         else:
#             if s.isEmpty():
#                 balanced = False
#             else:
#                 s.pop()
#
#         index = index + 1
#
#     if balanced and s.isEmpty():
#         return True
#     else:
#         return False


s = input("Enter a string: ")
print(parChecker(s))