<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>

#include<bits/stdc++.h>

class Solution {
public:
    // bool comparre(string a , string b){
        
    //     for(int i = 0 ;i < min(a.size() , b.size()) ; i++){
    //         if(a[i] != b[i]){
    //             int aaa = int(a[i] - '0') ;
    //             int bbb = int(b[i] - '0') ;
    //             if(aaa > bbb)return true ;
    //             else return false ;
    //         }
    //     }

    //     return (min(a.size() , b.size()) == a.size() ? true : false) ;
    // }
    string longestWord(vector<string>& words) {
        unordered_map<string,int> mp ;
        int len = 0 ; string ss ="" ;
        // sort(words.begin() , words.end()) ;
        for(auto it : words){
            mp[it]++ ;
        }
        for(auto it : words){ 
            int n = it.size() ;  
            int i = 0 ;
            while(i<it.size()){
                if(mp.find(it.substr(0,i+1))!=mp.end())
                    i++;
                else break;
            }

            if(i == it.size() ){
                if(ss.size() < n ){
                    ss = it ;
                }
                if(ss.size() == it.size()){
                    ss = min(ss , it) ;
                } 
            }
        }

        return ss ;
    }
};


// class Solution {
// public:
//     // bool check()
//     string longestWord(vector<string>& words) {
//         string ans="";
//         unordered_set<string> s(words.begin(),words.end());
//         for(auto x:words){
//             int i=0;
//             while(i<x.size()){
//                 if(s.find(x.substr(0,i+1))!=s.end())
//                     i++;
//                 else break;
//             }
//             if(i==x.size()){
//                 if(x.size()>ans.size()){
//                     ans=x;
//                 }
//                 if(x.size()==ans.size()){
//                     ans=min(ans,x);
//                 }
//             }
//         }
//         return ans;
//     }
// };
37753