<p>Given a balanced parentheses string <code>s</code>, return <em>the <strong>score</strong> of the string</em>.</p>

<p>The <strong>score</strong> of a balanced parentheses string is based on the following rule:</p>

<ul>
	<li><code>&quot;()&quot;</code> has score <code>1</code>.</li>
	<li><code>AB</code> has score <code>A + B</code>, where <code>A</code> and <code>B</code> are balanced parentheses strings.</li>
	<li><code>(A)</code> has score <code>2 * A</code>, where <code>A</code> is a balanced parentheses string.</li>
</ul>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;()&quot;
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;(())&quot;
<strong>Output:</strong> 2
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;()()&quot;
<strong>Output:</strong> 2
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= s.length &lt;= 50</code></li>
	<li><code>s</code> consists of only <code>&#39;(&#39;</code> and <code>&#39;)&#39;</code>.</li>
	<li><code>s</code> is a balanced parentheses string.</li>
</ul>

class Solution {
public:
    int scoreOfParentheses(string s) {
        int score=0;
        stack<string> st;
        for(int i=0;i<s.size();i++){
            string symbol(1,s[i]);
            int count=0;
            if(!st.empty() && symbol==")"){
                if(st.top()=="("){
                    count++;
                    st.pop();
                    int c=count+48;
                    string s(1,c);
                    st.push(s);
                }
                else{
                    int sum=0;
                    while(st.top()!="("){
                        int ch=stoi(st.top());
                        sum+=ch;
                        st.pop();
                    }
                    st.pop();
                    st.push(to_string(sum*2));
                }
            }
            else{
                st.push(symbol);
            }
        }
        while(!st.empty()){
            int x=stoi(st.top());
            st.pop();
            score+=x;
        }
        return score;
    }
};
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