<p>In a string composed of <code>&#39;L&#39;</code>, <code>&#39;R&#39;</code>, and <code>&#39;X&#39;</code> characters, like <code>&quot;RXXLRXRXL&quot;</code>, a move consists of either replacing one occurrence of <code>&quot;XL&quot;</code> with <code>&quot;LX&quot;</code>, or replacing one occurrence of <code>&quot;RX&quot;</code> with <code>&quot;XR&quot;</code>. Given the starting string <code>start</code> and the ending string <code>end</code>, return <code>True</code> if and only if there exists a sequence of moves to transform <code>start</code> to <code>end</code>.</p>

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

<pre>
<strong>Input:</strong> start = &quot;RXXLRXRXL&quot;, end = &quot;XRLXXRRLX&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> We can transform start to end following these steps:
RXXLRXRXL -&gt;
XRXLRXRXL -&gt;
XRLXRXRXL -&gt;
XRLXXRRXL -&gt;
XRLXXRRLX
</pre>

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

<pre>
<strong>Input:</strong> start = &quot;X&quot;, end = &quot;L&quot;
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>1 &lt;= start.length&nbsp;&lt;= 10<sup>4</sup></code></li>
	<li><code>start.length == end.length</code></li>
	<li>Both <code>start</code> and <code>end</code> will only consist of characters in <code>&#39;L&#39;</code>, <code>&#39;R&#39;</code>, and&nbsp;<code>&#39;X&#39;</code>.</li>
</ul>

class Solution {
public:
    bool canTransform(string start, string end) {
        if(start.size()!=end.size())    return false;
        string s1,s2;
        for(char ch:start){
            if(ch!='X')  s1+=ch;
        }   
        for(char ch:end){
            if(ch!='X')  s2+=ch;
        }
        if(s1!=s2)  return false;
        int p1=0,p2=0;
        int n = start.size();
        while(p1<n && p2<n){
            while(p1<n && start[p1]=='X')   p1++;
            while(p2<n && end[p2]=='X') p2++;
            if(p1==n && p2==n)  return true;
            if(p1==n || p2==n)  return false;
            if(start[p1]!=end[p2])  return false;
            if(start[p1]=='L' && p1<p2) return false;
            if(start[p1]=='R' && p1>p2) return false;
            p1++;
            p2++;
        }
        return true;
    }
};
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