<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:
    
    
    class trienode
    {
        public:
        
         char data;
         trienode* children[26];
         bool isterminal;
        
        trienode(char d)
        {
            data=d;
            for(int i=0;i<26;i++)
            {
                children[i]=NULL;
            }
            
            isterminal=false;
            
        }
          
        
    };
    
    
    class trie{
        
        public:
        
        
        trienode* root;
        
        
        trie()
        {
            root = new trienode('-');
        }
        
        
        void insertutil(string word,trienode* root)
        {
            
            
            if(word.length()==0)
            {
                root->isterminal=true;
                return;
            }
            
            int index = word[0]-'a';
            
            trienode* child;
            
            if(root->children[index]!=NULL)
            {
                child = root->children[index];
            }else{
                
                child = new trienode(word[0]);
                root->children[index]=child;
                
            }
            
            insertutil(word.substr(1),child);
            
            
        }
        
        void getmatchutil(string word,trienode* root,string& ans)
        {
            if(word.length()==0)
            {
                if(root->isterminal!=true)
                {
                    ans="";
                }
                return;
                
            }
            
                if(root->isterminal==true)
                {
                    return;
                }
            
            int index = word[0]-'a';
             trienode* child;
            
            if(root->children[index]!=NULL)
            {
              
                child=root->children[index];
                ans+=child->data;
            }else{
                
                ans="";
                return;
            }
            
            getmatchutil(word.substr(1),child,ans);
            
        }
        
        
        
        
        
        
        void insert(string word)
        {
            insertutil(word,root);
        }
        
         string getmatch(string word)
        {
            string ans="";
            getmatchutil(word,root,ans);
             return ans;
        }
        
        
        
        
        
        
    };
    
    
    
    
    string replaceWords(vector<string>& d, string s) {
        
        trie* t = new trie();
        
        
        for(int i=0;i<d.size();i++)
        {
            t->insert(d[i]);
        }
        
        vector<string> temp;
        string a="";
        
        for(int i=0;i<s.length();i++)
        {
           if(s.at(i)==' ')
           {
               if(a.size()>=1)
               {
                   temp.push_back(a);
               }
               a="";
           }else{
               
               a+=s.at(i);
           }
        }
        
               if(a.size()>=1)
               {
                   temp.push_back(a);
               }
        
        
        string ans="";
        
        for(int i=0;i<temp.size();i++)
        {
            string h = t->getmatch(temp[i]);
            if(h.length()==0)
            {
                ans=ans+" "+temp[i];
            }else{
                ans=ans+" "+h;
            }
        }
        
        
        
        return ans.substr(1);
        
    }
};
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