<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 TrieNode{
  public:
  char data;
  TrieNode* children[26];
  bool isTerminal;
  TrieNode(char ch)
  {
    data=ch;
    for(int i=0;i<26;i++)
    {
        children[i]=NULL;
    }
    isTerminal=false;
  
  }

};
class Trie{
    public:
    TrieNode* root;
    Trie(){
        root = new TrieNode('/');  }
    void insertUtil(TrieNode* root,string word)
    {
        if(word.length()==0)
        {
             root->isTerminal=true;
            
             return;
        }
        int index=word[0]-'a';
        TrieNode* child;
        if(root->children[index])
        {
            child=root->children[index];
           
        }
        else
        {
            child=new TrieNode(word[0]);
            
            root->children[index]=child;
        }
        insertUtil(child,word.substr(1));
    }
    void insertWord(string word)
    {
        insertUtil(root,word);
        return;
    }
   
    string searchUtil(TrieNode* root,string word,string str)
    {
        if(word.length()==0)
        {
            if(root->isTerminal)
            return str;
            else 
            return "";
        }
        int index=word[0]-'a';
        
        TrieNode* child;
         if(root->children[index])
        {
            child=root->children[index];
            if(root->isTerminal)
            return str;
        }
        else
        {
           if(root->isTerminal)
            return str;
            else 
            return "";
        }
       return searchUtil(child,word.substr(1),str+word[0]);

    }
    string search(string word)
    {
      return  searchUtil(root,word,"");
    }
};



class Solution {
public:
vector<string> split(string str, char delimiter)
{
  // Using str in a string stream
    stringstream ss(str);
    vector<string> res;
    string token;
    while (getline(ss, token, delimiter)) {
        res.push_back(token);
    }
    return res;
}
    string replaceWords(vector<string>& dictionary, string sentence) {
            Trie* t=new Trie();
            for(auto it : dictionary)
            {
                t->insertWord(it);
            }

             vector<string> res = split(sentence,' ');
            string ans="";
              for(auto it : res)
            {
                string temp= t->search(it);
                if(temp.length()==0)
                {
                    if(ans.length()==0)
                    ans=ans+it;
                    else
                    ans=ans+" "+it;
                }
                else
                {
                    if(ans.length()==0)
                    ans=ans+temp;
                    else
                    ans=ans+" "+temp;
                }
            }
            return ans;
        
    }
};
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