<p>In English, we have a concept called <strong>root</strong>, which can be followed by some other word to form another longer word - let&#39;s call this word <strong>derivative</strong>. For example, when the <strong>root</strong> <code>&quot;help&quot;</code> is followed by the word <code>&quot;ful&quot;</code>, we can form a derivative <code>&quot;helpful&quot;</code>.</p>

<p>Given a <code>dictionary</code> consisting of many <strong>roots</strong> and a <code>sentence</code> consisting of words separated by spaces, replace all the derivatives in the sentence with the <strong>root</strong> forming it. If a derivative can be replaced by more than one <strong>root</strong>, replace it with the <strong>root</strong> that has <strong>the shortest length</strong>.</p>

<p>Return <em>the <code>sentence</code></em> after the replacement.</p>

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

<pre>
<strong>Input:</strong> dictionary = [&quot;cat&quot;,&quot;bat&quot;,&quot;rat&quot;], sentence = &quot;the cattle was rattled by the battery&quot;
<strong>Output:</strong> &quot;the cat was rat by the bat&quot;
</pre>

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

<pre>
<strong>Input:</strong> dictionary = [&quot;a&quot;,&quot;b&quot;,&quot;c&quot;], sentence = &quot;aadsfasf absbs bbab cadsfafs&quot;
<strong>Output:</strong> &quot;a a b c&quot;
</pre>

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

<ul>
	<li><code>1 &lt;= dictionary.length &lt;= 1000</code></li>
	<li><code>1 &lt;= dictionary[i].length &lt;= 100</code></li>
	<li><code>dictionary[i]</code> consists of only lower-case letters.</li>
	<li><code>1 &lt;= sentence.length &lt;= 10<sup>6</sup></code></li>
	<li><code>sentence</code> consists of only lower-case letters and spaces.</li>
	<li>The number of words in <code>sentence</code> is in the range <code>[1, 1000]</code></li>
	<li>The length of each word in <code>sentence</code> is in the range <code>[1, 1000]</code></li>
	<li>Every two consecutive words in <code>sentence</code> will be separated by exactly one space.</li>
	<li><code>sentence</code> does not have leading or trailing spaces.</li>
</ul>

class Solution {
public:
    string replaceWords(vector<string>& dictionary, string sentence) {
        
        std::vector<std::string> palabras;
        bool reg=false;
        std::string res;
        int ini=0,fin=0;

        for (int i=0; i<sentence.size();i++){

            if(sentence[i] == ' '){
                palabras.push_back(sentence.substr(ini, i - ini));
                ini=i+1;
            }
        }
        if (ini < sentence.size()) {
            palabras.push_back(sentence.substr(ini));
        }

        for (const std::string& pal : palabras){
              if(reg) res += ' ';
              reg=true;
             std::vector<std::string> raices;
             bool tiene=false;
           for(const std::string& raiz : dictionary){
                 std::string temp, temp2;
               for(int i=0; i< raiz.size(); i++){
                if(pal[i] != raiz[i]){
                    break;
                } 
                else{
                    temp2.push_back(pal[i]);
                } 
                if(temp2 == raiz){
                    tiene=true;
                    temp= temp2;
                    break;
                }
               }
             if(!temp.empty()){
                raices.push_back(temp);
                            
             } 
           }
            if (!tiene){
                res += pal;                
            }else{
                   std::string prue;
                for (const std::string& ult : raices){
                    if(!prue.empty()){
                        if(prue.size()>ult.size()) prue = ult;
                    }else prue = ult;
                }
                 res +=prue;
            }
        }
        return res;
    }
};
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