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Python 3: From Beginner to Advanced

Solution Review: Check Whether the Brackets are Balanced

Understand how to determine if brackets in a string are balanced by using a counter variable. Explore the logic of incrementing and decrementing the counter as you iterate through the characters, ensuring no closing bracket appears before a matching opening bracket and that all brackets properly close.

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Solution

Python 3.5
def check_balance(brackets):
    check = 0
    for bracket in brackets:
        if bracket == '[':
            check += 1
        elif bracket == ']':
            check -= 1
        if check < 0:
            break
    return check == 0
bracket_string = '[[[[]]'
print(check_balance(bracket_string))

Explanation

The solution relies on the value of the check variable declared at line 2, which is updated in each iteration.

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