<p>Given a string <code>s</code> of lowercase letters, you need to find the maximum number of <strong>non-empty</strong> substrings of <code>s</code> that meet the following conditions:</p>

<ol>
	<li>The substrings do not overlap, that is for any two substrings <code>s[i..j]</code> and <code>s[x..y]</code>, either <code>j &lt; x</code> or <code>i &gt; y</code> is true.</li>
	<li>A substring that contains a certain character <code>c</code> must also contain all occurrences of <code>c</code>.</li>
</ol>

<p>Find <em>the maximum number of substrings that meet the above conditions</em>. If there are multiple solutions with the same number of substrings, <em>return the one with minimum total length. </em>It can be shown that there exists a unique solution of minimum total length.</p>

<p>Notice that you can return the substrings in <strong>any</strong> order.</p>

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

<pre>
<strong>Input:</strong> s = &quot;adefaddaccc&quot;
<strong>Output:</strong> [&quot;e&quot;,&quot;f&quot;,&quot;ccc&quot;]
<b>Explanation:</b>&nbsp;The following are all the possible substrings that meet the conditions:
[
&nbsp; &quot;adefaddaccc&quot;
&nbsp; &quot;adefadda&quot;,
&nbsp; &quot;ef&quot;,
&nbsp; &quot;e&quot;,
  &quot;f&quot;,
&nbsp; &quot;ccc&quot;,
]
If we choose the first string, we cannot choose anything else and we&#39;d get only 1. If we choose &quot;adefadda&quot;, we are left with &quot;ccc&quot; which is the only one that doesn&#39;t overlap, thus obtaining 2 substrings. Notice also, that it&#39;s not optimal to choose &quot;ef&quot; since it can be split into two. Therefore, the optimal way is to choose [&quot;e&quot;,&quot;f&quot;,&quot;ccc&quot;] which gives us 3 substrings. No other solution of the same number of substrings exist.
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;abbaccd&quot;
<strong>Output:</strong> [&quot;d&quot;,&quot;bb&quot;,&quot;cc&quot;]
<b>Explanation: </b>Notice that while the set of substrings [&quot;d&quot;,&quot;abba&quot;,&quot;cc&quot;] also has length 3, it&#39;s considered incorrect since it has larger total length.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> contains only lowercase English letters.</li>
</ul>

class Solution {
public:
    vector<string> maxNumOfSubstrings(string s) {
        unordered_map<char,vector<int>>h;
        for(int i = 'a'; i <='z';i++) h[i] = {INT_MAX,INT_MIN};
        for(int i = 0; i < s.size(); i++){
           h[s[i]][0] = min(h[s[i]][0], i);
           h[s[i]][1] = max(h[s[i]][1], i);
        }
        
       for(int i = 0; i < s.size(); i++){
         for(char j ='a'; j <='z' ; j++){
             if(h[j][0]==INT_MAX) continue;
             if(h[j][0] <= i and h[j][1] >= i) {
                 h[j][0] = min(h[s[i]][0], h[j][0]);
                 h[j][1] = max(h[s[i]][1], h[j][1]);
             }
         }
       }
       vector<vector<int>>intervals;
       for(char i = 'a'; i <='z'; i++){
           if(h[i][0]!=INT_MAX)
           {
              //cout << h[i][0] << " " << h[i][1] << endl;
              intervals.push_back(h[i]);
           }
       }
       
       sort(intervals.begin(),intervals.end(), [](const vector<int>&a, vector<int>&b){
           return a[1] < b[1];
       });
        
        vector<string>sol;
        int last=-1;
        for(int i = 0; i < intervals.size(); i++){
            if(intervals[i][0] > last){
                sol.push_back(s.substr(intervals[i][0], intervals[i][1]-intervals[i][0]+1));
                last = intervals[i][1];
            }
        }    
        return sol;
    }
};
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