856. Score of Parentheses

Problem Link

Description

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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.
• AB has score A + B, where A and B are balanced parentheses strings.
• (A) has score 2 * A, where A is a balanced parentheses string.

 

Example 1:

Input: s = "()"
Output: 1

Example 2:

Input: s = "(())"
Output: 2

Example 3:

Input: s = "()()"
Output: 2

 

Constraints:

• 2 <= s.length <= 50
• s consists of only '(' and ')'.
• s is a balanced parentheses string.

Solution

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Python3

class Solution:
    def scoreOfParentheses(self, s: str) -> int:
        stack = []
        curr = 0
        
        for x in s:
            if x == "(":
                stack.append(curr)
                curr = 0
            else:
                curr = stack.pop() + max(curr * 2, 1)
        
        return curr