<p>Given an array of strings <code>words</code> representing an English Dictionary, return <em>the longest word in</em> <code>words</code> <em>that can be built one character at a time by other words in</em> <code>words</code>.</p>

<p>If there is more than one possible answer, return the longest word with the smallest lexicographical order. If there is no answer, return the empty string.</p>

<p>Note that the word should be built from left to right with each additional character being added to the end of a previous word.&nbsp;</p>

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

<pre>
<strong>Input:</strong> words = [&quot;w&quot;,&quot;wo&quot;,&quot;wor&quot;,&quot;worl&quot;,&quot;world&quot;]
<strong>Output:</strong> &quot;world&quot;
<strong>Explanation:</strong> The word &quot;world&quot; can be built one character at a time by &quot;w&quot;, &quot;wo&quot;, &quot;wor&quot;, and &quot;worl&quot;.
</pre>

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

<pre>
<strong>Input:</strong> words = [&quot;a&quot;,&quot;banana&quot;,&quot;app&quot;,&quot;appl&quot;,&quot;ap&quot;,&quot;apply&quot;,&quot;apple&quot;]
<strong>Output:</strong> &quot;apple&quot;
<strong>Explanation:</strong> Both &quot;apply&quot; and &quot;apple&quot; can be built from other words in the dictionary. However, &quot;apple&quot; is lexicographically smaller than &quot;apply&quot;.
</pre>

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

<ul>
	<li><code>1 &lt;= words.length &lt;= 1000</code></li>
	<li><code>1 &lt;= words[i].length &lt;= 30</code></li>
	<li><code>words[i]</code> consists of lowercase English letters.</li>
</ul>

class Solution {
    struct Node{
        Node * links[26];
        bool flag=false;
    };
    
public:
    static int comp(string s1,string s2){
        if(s1.length()==s2.length())
         return s1<s2;
     return s1.length()<s2.length();
     }
    string longestWord(vector<string>& words) {
        sort(words.begin(),words.end(),comp);
        for(auto i:words)
         cout<<i<<" ";
        cout<<endl;
        Node *root1 =new Node();
        // Node *root=root1;
        string ans="";int f=-1;
        for(int i=0;i<words.size();i++)
        {
            Node *root=root1;int c=0;
            cout<<words[i]<<endl;int fg=0;
            for(int j=0;j<words[i].length();j++)
            {
                
                
                if(root->links[words[i][j]-'a']!=NULL)
                {
                    root=root->links[words[i][j]-'a'];
                    cout<<"found ";
                    c++;
                }
                else if(words[i].length()-j==1 ){
                 root->links[words[i][j]-'a']=new Node();
                 root=root->links[words[i][j]-'a'];
                 cout<<"inserted "<<" ";
                 fg=1;
                }
                else
                 break;
            }
            cout<<c<<endl;
            if(f<c&fg==1)
             {
             f=c;
             ans=words[i];
             }
            cout<<endl;
            root->flag=true;
        }
       return ans;
    }
};
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