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class Solution {
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 public:
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  int scoreOfParentheses(string s) {
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    stack<int> st;
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    int score = 0;
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    for (int i = 0; i < s.size(); i++) {
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      if (s[i] == '(') {
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        st.push(score);
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        score = 0;
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      } else {
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        score = st.top() + max(2 * score, 1);
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        st.pop();
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      }
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    }
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    return score;
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  }
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};