<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 points1 = 0, points2 = 0;
        stack<char> st;
        for (char i : s) {
            if (i == 'b')
                st.push(i);
            else if (i == 'a') {
                if (!st.empty() && st.top() == 'b') {
                    st.pop();
                    points1 += y;
                } else if (st.empty() || st.top() == 'a')
                    st.push('a');
            } else {
                int a1 = 0;
                int b1 = 0;
                while (!st.empty()) {
                    if (st.top() == 'b')
                        b1++;
                    else
                        a1++;
                    st.pop();
                }
                points1 += min(a1, b1) * x;
            }
        }
        int a = 0, b = 0;
        while (!st.empty()) {
            if (st.top() == 'a')
                a++;
            else
                b++;
            st.pop();
        }
        points1 += min(b, a) * x;
        for (char i : s) {
            if (i == 'a')
                st.push(i);
            else if (i == 'b') {
                if (!st.empty() && st.top() == 'a') {
                    st.pop();
                    points2 += x;
                } else if (st.empty() || st.top() == 'b')
                    st.push('b');

            } else {
                int a1 = 0;
                int b1 = 0;
                while (!st.empty()) {
                    if (st.top() == 'b')
                        b1++;
                    else
                        a1++;
                    st.pop();
                }
                points2 += min(a1, b1) * y;
            }
        }
        a = 0, b = 0;
        while (!st.empty()) {
            if (st.top() == 'b')
                b++;
            else
                a++;
            st.pop();
        }
        points2 += min(b, a) * y;
        cout << points1 << " " << points2 << endl;
        return max(points1, points2);
    }
};
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