Question

Write code to check if parentheses in a string are balanced using a stack.

Answer 1

Here is the code.

def is_balanced(expression):
    stack = Stack()
    opening_brackets = "([{"
    closing_brackets = ")]}"
    for char in expression:
        if char in opening_brackets:
            stack.push(char)
        elif char in closing_brackets:
            if stack.is_empty():
                return False
            top = stack.pop()
            if opening_brackets.index(top) != closing_brackets.index(char):
                return False
    return stack.is_empty()

# Example usage:
expression = "{[()]}"
print(is_balanced(expression))  # Output: True