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class Solution {
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 public:
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  // calculate the frequency of string s
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  vector<int> giveMeFreq(string s) {
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    vector<int> freq(26, 0);
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    for (int i = 0; i < s.length(); i++) {
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      freq[s[i] - 'a']++;
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    }
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    return freq;
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  }
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  vector<string> wordSubsets(vector<string> &words1, vector<string> &words2) {
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    vector<string> ans;             // store ans
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    vector<int> max_Freq_w2(26, 0); // store max freq of each character present in word2 stirngs
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    // we will Iterate over word to and try to find max freq for each character
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    // present in all strings.
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    for (auto &x : words2) {
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      vector<int> freq = giveMeFreq(x);
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      for (int i = 0; i < 26; i++) {
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        max_Freq_w2[i] = max(freq[i], max_Freq_w2[i]); // upadate freq to max freq
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      }
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    }
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    // we will iterate for each string in words1 ans if it have all charaters
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    // present in freq array with freq >= that     then we will add it to ans
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    for (auto &x : words1) {
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      vector<int> freq = giveMeFreq(x); // gives freq of characters for word in words1
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      bool flag = true;
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      for (int i = 0; i < 26; i++) {
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        if (freq[i] < max_Freq_w2[i]) // specifies that word did not have all
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                                      // the characters from word2 array
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        {
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          flag = false;
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          break;
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        }
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      }
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      if (flag) ans.push_back(x); // string x is Universal string
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    }
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    return ans;
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  }
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};