Score of Parentheses — LeetCode 856 Python Solution

The problem

Given a balanced parentheses string s, return the score of the string. The score of a balanced parentheses string is based on the following rule: "()" has score 1.

Example

Input

s = "()"

Output

1

Python solution

class Solution:
    def scoreOfParentheses(self, s: str) -> int:
        ans = d = 0
        for i, c in enumerate(s):
            if c == '(':
                d += 1
            else:
                d -= 1
                if s[i - 1] == '(':
                    ans += 1 << d
        return ans

Complexity

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 856. Score of Parentheses is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Stack.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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