<p>In a project, you have a list of required skills <code>req_skills</code>, and a list of people. The <code>i<sup>th</sup></code> person <code>people[i]</code> contains a list of skills that the person has.</p>

<p>Consider a sufficient team: a set of people such that for every required skill in <code>req_skills</code>, there is at least one person in the team who has that skill. We can represent these teams by the index of each person.</p>

<ul>
	<li>For example, <code>team = [0, 1, 3]</code> represents the people with skills <code>people[0]</code>, <code>people[1]</code>, and <code>people[3]</code>.</li>
</ul>

<p>Return <em>any sufficient team of the smallest possible size, represented by the index of each person</em>. You may return the answer in <strong>any order</strong>.</p>

<p>It is <strong>guaranteed</strong> an answer exists.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> req_skills = ["java","nodejs","reactjs"], people = [["java"],["nodejs"],["nodejs","reactjs"]]
<strong>Output:</strong> [0,2]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> req_skills = ["algorithms","math","java","reactjs","csharp","aws"], people = [["algorithms","math","java"],["algorithms","math","reactjs"],["java","csharp","aws"],["reactjs","csharp"],["csharp","math"],["aws","java"]]
<strong>Output:</strong> [1,2]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= req_skills.length &lt;= 16</code></li>
	<li><code>1 &lt;= req_skills[i].length &lt;= 16</code></li>
	<li><code>req_skills[i]</code> consists of lowercase English letters.</li>
	<li>All the strings of <code>req_skills</code> are <strong>unique</strong>.</li>
	<li><code>1 &lt;= people.length &lt;= 60</code></li>
	<li><code>0 &lt;= people[i].length &lt;= 16</code></li>
	<li><code>1 &lt;= people[i][j].length &lt;= 16</code></li>
	<li><code>people[i][j]</code> consists of lowercase English letters.</li>
	<li>All the strings of <code>people[i]</code> are <strong>unique</strong>.</li>
	<li>Every skill in <code>people[i]</code> is a skill in <code>req_skills</code>.</li>
	<li>It is guaranteed a sufficient team exists.</li>
</ul>

class Solution {
public:
unordered_map<string,int> dp;
void f(int i , int mask, int req, vector<int>&temp, vector<int>&res,vector<int> &people_skill)
{
    if(i>=people_skill.size())
    {
        if(mask == req)
        {
            if(res.size()==0 || res.size()>temp.size())
              {
                res = temp;

              }
        }
        return;
    }
    if(res.size() and res.size()<=temp.size())
         return ;
    string key= to_string(i)+"-"+to_string(mask);
    if(dp.find(key)!=dp.end())
    {
        if(dp[key]<=temp.size())
        {
            return;
        }
    }
    if((people_skill[i]|mask)!=mask)
    {
        temp.push_back(i);
        f(i+1,mask|people_skill[i],req,temp,res,people_skill);
        temp.pop_back();
    }
    
    f(i+1,mask,req,temp,res,people_skill);
    dp[key] = temp.size()==0 ? -1:temp.size();
    
}
    vector<int> smallestSufficientTeam(vector<string>& req_skills, vector<vector<string>>& people) {
        unordered_map<string, int> mp;
      for(int i = 0 ; i<req_skills.size();i++)
      {
        mp[req_skills[i]]=i;
      }
        int req  = (1<<req_skills.size())-1;
    vector<int> people_skills, res, temp;
    for(auto skills:people)
    {
        int x =0;
        for(auto it:skills)
        {
            if(mp.find(it)!=mp.end())
            {
                x|=1<<mp[it];
            }
        }
        people_skills.push_back(x);
    }
    f(0,0,req,temp,res,people_skills);
    
    return res;

    }
};
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