<p><strong>HTML entity parser</strong> is the parser that takes HTML code as input and replace all the entities of the special characters by the characters itself.</p>

<p>The special characters and their entities for HTML are:</p>

<ul>
	<li><strong>Quotation Mark:</strong> the entity is <code>&amp;quot;</code> and symbol character is <code>&quot;</code>.</li>
	<li><strong>Single Quote Mark:</strong> the entity is <code>&amp;apos;</code> and symbol character is <code>&#39;</code>.</li>
	<li><strong>Ampersand:</strong> the entity is <code>&amp;amp;</code> and symbol character is <code>&amp;</code>.</li>
	<li><strong>Greater Than Sign:</strong> the entity is <code>&amp;gt;</code> and symbol character is <code>&gt;</code>.</li>
	<li><strong>Less Than Sign:</strong> the entity is <code>&amp;lt;</code> and symbol character is <code>&lt;</code>.</li>
	<li><strong>Slash:</strong> the entity is <code>&amp;frasl;</code> and symbol character is <code>/</code>.</li>
</ul>

<p>Given the input <code>text</code> string to the HTML parser, you have to implement the entity parser.</p>

<p>Return <em>the text after replacing the entities by the special characters</em>.</p>

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

<pre>
<strong>Input:</strong> text = &quot;&amp;amp; is an HTML entity but &amp;ambassador; is not.&quot;
<strong>Output:</strong> &quot;&amp; is an HTML entity but &amp;ambassador; is not.&quot;
<strong>Explanation:</strong> The parser will replace the &amp;amp; entity by &amp;
</pre>

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

<pre>
<strong>Input:</strong> text = &quot;and I quote: &amp;quot;...&amp;quot;&quot;
<strong>Output:</strong> &quot;and I quote: \&quot;...\&quot;&quot;
</pre>

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

<ul>
	<li><code>1 &lt;= text.length &lt;= 10<sup>5</sup></code></li>
	<li>The string may contain any possible characters out of all the 256 ASCII characters.</li>
</ul>

class Solution {
public:
    void find(string as,string tr,vector<int>& flag){
        size_t found=as.find(tr);
        while(found!=string::npos){
            flag[found]=1;
            found=as.find(tr,found+1);
        }
    }

    string entityParser(string text) {
        unordered_map<string,string> mp;

        mp["&quot;"]="\"";
        mp["&apos;"]="\'";
        mp["&amp;"]="&";
        mp["&gt;"]=">";
        mp["&lt;"]="<";
        mp["&frasl;"]="/";


        vector<int> flag(text.size(),0);

        for(auto itr=mp.begin();itr!=mp.end();++itr){
            find(text,itr->first,flag);
        }

        int index=0;
        string as="",ret="";

        while(index<text.size()){
            if(flag[index]){
                ret+=as;
                as="";
                while(mp.find(as)==mp.end()){
                    as+=text[index];
                    //cout<<index<<' ';
                    index++;
                }
                ret+=mp[as];
                as="";
            }
            else{
                as+=text[index];
                index++;
            }
        }
        ret+=as;
        return ret;
    }
};
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