score-of-parenthesis.py

import unittest


def scoreOfParentheses(s: str) -> int:
    ans = bal = 0

    for i, x in enumerate(s):
        if x == "(":
            bal += 1
        else:
            bal -= 1
            if s[i - 1] == "(":
                ans += 1 << bal
    return ans


class TestStringMethods(unittest.TestCase):
    def test_all_cases(self):
        self.assertEqual(scoreOfParentheses("()"), 1)
        self.assertEqual(scoreOfParentheses("(())"), 2)
        self.assertEqual(scoreOfParentheses("()()"), 2)
        self.assertEqual(scoreOfParentheses("(()(()))"), 6)


if __name__ == "__main__":
    unittest.main()