<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 {
public:
    uint bit[30]={1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,65536*2,65536*4,65536*8,65536*16,65536*32,65536*64,65536*128,65536*256,65536*512,65536*1024,65536*2048,65536*4096,65536*8192};
    uint bits[30];
    string longestWord(vector<string>& words) {
        sort(words.begin(),words.end(),[](string a, string i){
            if(a.length()==i.length())
            return a.compare(i)<0;
            return a.length()>i.length();
        });
        for(int i=0;i<30;i=i+1)
        {
        //bit[i]=1<<i;
        for(int i1=i;i1>=0;i1=i1-1)
        bits[i]=bits[i]|bit[i1];
        //cout<<bits[i]<<" ";
        }
        for(int i=0;i<words.size();i=i+1)
        {
            string output=words[i];
            int found=output.length()-1;
            int biti=0;
            for(int i1=i+1;i1<words.size();i1=i1+1)
            {
                if(words[i1].length()<output.length())
                if(output.substr(0,words[i1].length())==words[i1])
                {
                    if(!(biti&bit[words[i1].length()]))
                    {
                        biti=biti|bit[words[i1].length()];
                        found=found-1;
                    }
                }
            }
            cout<<found<<" ";
            //if(output.length()>2)
            //{
            //if((biti&bits[output.length()-1-1])==bits[output.length()-1-1])
            //return output;
            //}
            //else
            //{
                if(found==0)
                return output;
            //}
            cout<<biti<<" ,";
        }
        return "";
    }
};
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