<p>You are given a string <code>s</code> and two integers <code>x</code> and <code>y</code>. You can perform two types of operations any number of times.</p>

<ul>
	<li>Remove substring <code>&quot;ab&quot;</code> and gain <code>x</code> points.

	<ul>
		<li>For example, when removing <code>&quot;ab&quot;</code> from <code>&quot;c<u>ab</u>xbae&quot;</code> it becomes <code>&quot;cxbae&quot;</code>.</li>
	</ul>
	</li>
	<li>Remove substring <code>&quot;ba&quot;</code> and gain <code>y</code> points.
	<ul>
		<li>For example, when removing <code>&quot;ba&quot;</code> from <code>&quot;cabx<u>ba</u>e&quot;</code> it becomes <code>&quot;cabxe&quot;</code>.</li>
	</ul>
	</li>
</ul>

<p>Return <em>the maximum points you can gain after applying the above operations on</em> <code>s</code>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;cdbcbbaaabab&quot;, x = 4, y = 5
<strong>Output:</strong> 19
<strong>Explanation:</strong>
- Remove the &quot;ba&quot; underlined in &quot;cdbcbbaaa<u>ba</u>b&quot;. Now, s = &quot;cdbcbbaaab&quot; and 5 points are added to the score.
- Remove the &quot;ab&quot; underlined in &quot;cdbcbbaa<u>ab</u>&quot;. Now, s = &quot;cdbcbbaa&quot; and 4 points are added to the score.
- Remove the &quot;ba&quot; underlined in &quot;cdbcb<u>ba</u>a&quot;. Now, s = &quot;cdbcba&quot; and 5 points are added to the score.
- Remove the &quot;ba&quot; underlined in &quot;cdbc<u>ba</u>&quot;. Now, s = &quot;cdbc&quot; and 5 points are added to the score.
Total score = 5 + 4 + 5 + 5 = 19.</pre>

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

<pre>
<strong>Input:</strong> s = &quot;aabbaaxybbaabb&quot;, x = 5, y = 4
<strong>Output:</strong> 20
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= x, y &lt;= 10<sup>4</sup></code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
</ul>

class Solution {
public:
    int maximumGain(string s, int x, int y) {
        int ans = 0;
        if( x > y)
        {
            stack<char>st;
            for(int i=0;i<s.size();i++)
            {
                if(st.empty() == 1 || (s[i] != 'a' && s[i] != 'b'))
                st.push(s[i]);
                else if(s[i] == 'b' && st.top() == 'a')
                {
                    ans= ans+x;
                    st.pop();
                }
                else
                {
                    st.push(s[i]);
                }
            }
            stack<char>temp;
            while(st.empty() != 1)
            {
                if(temp.empty() == 1)
                temp.push(st.top());
                else if(st.top() == 'b' && temp.top() == 'a')
                {
                    ans= ans+y;
                    temp.pop();
                }
                else
                temp.push(st.top());
                st.pop();
            }
        }
        else
        {
            stack<char>st;
            for(int i=0;i<s.size();i++)
            {
                if(st.empty() == 1 || (s[i] != 'a' && s[i] != 'b'))
                st.push(s[i]);
                else if(s[i] == 'a' && st.top() == 'b')
                {
                    ans= ans+y;
                    st.pop();
                }
                else
                {
                    st.push(s[i]);
                }
            }
            stack<char>temp;
            while(st.empty() != 1)
            {
                if(temp.empty() == 1)
                temp.push(st.top());
                else if(st.top() == 'a' && temp.top() == 'b')
                {
                    ans= ans+x;
                    temp.pop();
                }
                else
                temp.push(st.top());
                st.pop();
        }
        }
       return ans;
    }
};
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