<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) {
        stack<char>st;
        int c=0,d=0;
        for(auto &i:s){
            d++;
            if(i=='a'||i=='b'){
                if(x>=y){
                    if(i=='b'){
                        if(!st.empty()&&st.top()=='a'){
                            c+=x;
                            st.pop();
                        }
                        else{
                            st.push(i);
                        }
                    }
                    else{
                        st.push(i);
                    }
                    
                }
                else{
                    if(i=='a'){
                        if(!st.empty()&&st.top()=='b'){
                            c+=y;
                            st.pop();
                        }
                        else{
                            st.push(i);
                        }
                    }
                    else{
                        st.push(i);
                    }
                }
                
            }
            else{
                int b=0,a=0;
                while(!st.empty()){
                    char z=st.top();
                    st.pop();
                    if(z=='a'){
                        if(b){
                            c+=x;
                            b--;
                        }
                        else{
                            a++;
                        }
                    }
                    else{
                        if(a){
                            c+=y;
                            a--;
                        }
                        else
                        {
                            b++;
                        }
                    }
                }
            }
        }
    
        int b=0,a=0;
                while(!st.empty()){
                    
                    char z=st.top();

                    st.pop();
                    if(z=='a'){
                       
                        if(b){
                            c+=x;
                            b--;
                        }
                        else{
                            a++;
                        }
                    }
                    else{
                        
                        if(a){
                            c+=y;
                            a--;
                        }
                        else
                        {
                            b++;
                        }
                    }
                }
        cout<<c<<endl;
        
        return c;
    }

};
18421