<p>Given a string array <code>words</code>, return <em>an array of all characters that show up in all strings within the </em><code>words</code><em> (including duplicates)</em>. You may return the answer in <strong>any order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> words = ["bella","label","roller"]
<strong>Output:</strong> ["e","l","l"]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> words = ["cool","lock","cook"]
<strong>Output:</strong> ["c","o"]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= words.length &lt;= 100</code></li>
	<li><code>1 &lt;= words[i].length &lt;= 100</code></li>
	<li><code>words[i]</code> consists of lowercase English letters.</li>
</ul>

class Solution {
public:
    vector<string> commonChars(vector<string>& words) {
        
        vector<int> minfreq(26, INT_MAX);

        for(string word: words){

            vector<int> freq(26,0);

            for(char c: word){
                freq[c-'a']++;
            }

            for(int  i=0;i<26;i++){
                minfreq[i]= min(minfreq[i], freq[i]);
            }
        }

        vector<string> res;

        for(int i=0;i<26;i++){
            while(minfreq[i]>0){
                res.push_back(string(1, i+'a'));
                minfreq[i]--;
            }
        }

        return res;
    }

};
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