<p>Given an array of strings <code>words</code> and an integer <code>k</code>, return <em>the </em><code>k</code><em> most frequent strings</em>.</p>

<p>Return the answer <strong>sorted</strong> by <strong>the frequency</strong> from highest to lowest. Sort the words with the same frequency by their <strong>lexicographical order</strong>.</p>

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

<pre>
<strong>Input:</strong> words = [&quot;i&quot;,&quot;love&quot;,&quot;leetcode&quot;,&quot;i&quot;,&quot;love&quot;,&quot;coding&quot;], k = 2
<strong>Output:</strong> [&quot;i&quot;,&quot;love&quot;]
<strong>Explanation:</strong> &quot;i&quot; and &quot;love&quot; are the two most frequent words.
Note that &quot;i&quot; comes before &quot;love&quot; due to a lower alphabetical order.
</pre>

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

<pre>
<strong>Input:</strong> words = [&quot;the&quot;,&quot;day&quot;,&quot;is&quot;,&quot;sunny&quot;,&quot;the&quot;,&quot;the&quot;,&quot;the&quot;,&quot;sunny&quot;,&quot;is&quot;,&quot;is&quot;], k = 4
<strong>Output:</strong> [&quot;the&quot;,&quot;is&quot;,&quot;sunny&quot;,&quot;day&quot;]
<strong>Explanation:</strong> &quot;the&quot;, &quot;is&quot;, &quot;sunny&quot; and &quot;day&quot; are the four most frequent words, with the number of occurrence being 4, 3, 2 and 1 respectively.
</pre>

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

<ul>
	<li><code>1 &lt;= words.length &lt;= 500</code></li>
	<li><code>1 &lt;= words[i].length &lt;= 10</code></li>
	<li><code>words[i]</code> consists of lowercase English letters.</li>
	<li><code>k</code> is in the range <code>[1, The number of <strong>unique</strong> words[i]]</code></li>
</ul>

<p>&nbsp;</p>
<p><strong>Follow-up:</strong> Could you solve it in <code>O(n log(k))</code> time and <code>O(n)</code> extra space?</p>




class Solution {
public:

    


    map<string,int>freq;
    

    vector<string> topKFrequent(vector<string>& words, int k) {
        
        auto customComp = [](const std::pair<int, std::string>& a, const std::pair<int, std::string>& b) {
        if (a.first != b.first) {
            return a.first < b.first;  // Sort by the integer in descending order
        }
        return a.second > b.second;    // If integers are equal, sort by the string in ascending order
    };



        set<pair<int,string>,decltype(customComp)>st(customComp);
        
        for(int i=0;i<words.size();i++)
        {
            if(st.size()<k)
            {
                auto f = st.find({freq[words[i]],words[i]});

                if(f!=st.end())
                st.erase(f);
                freq[words[i]]++;
                st.insert({freq[words[i]],words[i]});
            }

            else
            {
                auto f = st.find({freq[words[i]],words[i]});
                freq[words[i]]++;

                if(f!=st.end())
                {
                    st.erase(f);
                    st.insert({freq[words[i]],words[i]});
                }

                else
                {   
                    st.insert({freq[words[i]],words[i]});
                    st.erase(st.begin());
                }
            }
        }

        vector<string>res;

        for(auto u:st)
        {
            res.push_back(u.second);
            //cout<<u.first<<" "<<u.second<<endl;
        }

        reverse(res.begin(),res.end());

        //sort(res.begin(),res.end(),comp);

        return res;

    }
};
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