<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) {
        
        unordered_map<char, int> common;
        vector<string> result;

        for(int i = 0; i < words[0].size(); i++)
            common[words[0][i]]++;

        for(int word = 1; word < words.size(); word++)
        {
            unordered_map<char, int> current;
            for(auto chr : words[word])
            {
                if(common.find(chr) != common.end() && common[chr] > 0)
                {
                    common[chr]--;
                    current[chr]++;
                }
            }
            common = current;
        }

        for(auto chrs : common)
        {
            while(chrs.second)
            {
                result.push_back(string(1, chrs.first));
                chrs.second--;
            }
        }

        return result;
        
    }
};
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