<p>You are given two string arrays <code>words1</code> and <code>words2</code>.</p>

<p>A string <code>b</code> is a <strong>subset</strong> of string <code>a</code> if every letter in <code>b</code> occurs in <code>a</code> including multiplicity.</p>

<ul>
	<li>For example, <code>&quot;wrr&quot;</code> is a subset of <code>&quot;warrior&quot;</code> but is not a subset of <code>&quot;world&quot;</code>.</li>
</ul>

<p>A string <code>a</code> from <code>words1</code> is <strong>universal</strong> if for every string <code>b</code> in <code>words2</code>, <code>b</code> is a subset of <code>a</code>.</p>

<p>Return an array of all the <strong>universal</strong> strings in <code>words1</code>. 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> words1 = [&quot;amazon&quot;,&quot;apple&quot;,&quot;facebook&quot;,&quot;google&quot;,&quot;leetcode&quot;], words2 = [&quot;e&quot;,&quot;o&quot;]
<strong>Output:</strong> [&quot;facebook&quot;,&quot;google&quot;,&quot;leetcode&quot;]
</pre>

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

<pre>
<strong>Input:</strong> words1 = [&quot;amazon&quot;,&quot;apple&quot;,&quot;facebook&quot;,&quot;google&quot;,&quot;leetcode&quot;], words2 = [&quot;l&quot;,&quot;e&quot;]
<strong>Output:</strong> [&quot;apple&quot;,&quot;google&quot;,&quot;leetcode&quot;]
</pre>

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

<ul>
	<li><code>1 &lt;= words1.length, words2.length &lt;= 10<sup>4</sup></code></li>
	<li><code>1 &lt;= words1[i].length, words2[i].length &lt;= 10</code></li>
	<li><code>words1[i]</code> and <code>words2[i]</code> consist only of lowercase English letters.</li>
	<li>All the strings of <code>words1</code> are <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    vector<string> wordSubsets(vector<string>& words1, vector<string>& words2) {
        int n = words1.size(), m = words2.size();
        vector<vector<int>> freq(m, vector<int>(26, 0));

        for(int i=0;i<m;i++){
            string word = words2[i];
            for(auto ch : word){
                freq[i][ch - 'a']++;
            }
        }

        vector<int> maximum(26, 0);

        for(int i=0;i<26;i++){
            int maxi = 0;

            for(int j=0;j<m;j++){
                maxi = max(maxi, freq[j][i]);
            }

            maximum[i] = maxi;
        }

        // for(auto m : maximum){
        //     cout<<m<<" ";
        // }
        // cout<<endl;

        vector<int> temp(26, 0);
        vector<string> res;
        
        for(auto word : words1){
            for(int i=0;i<26;i++){
                temp[i] = 0;
            }

            for(auto ch : word){
                temp[ch - 'a']++;
            }

            bool valid = true;
            for(int i=0;i<26;i++){
                if(maximum[i] > temp[i]){
                    valid = false;
                    break;
                }
            }

            if(valid){
                res.push_back(word);
            }
        }

        return res;
    }
};
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