<p>You are given an array of integers&nbsp;<code>nums</code>, there is a sliding window of size <code>k</code> which is moving from the very left of the array to the very right. You can only see the <code>k</code> numbers in the window. Each time the sliding window moves right by one position.</p>

<p>Return <em>the max sliding window</em>.</p>

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

<pre>
<strong>Input:</strong> nums = [1,3,-1,-3,5,3,6,7], k = 3
<strong>Output:</strong> [3,3,5,5,6,7]
<strong>Explanation:</strong> 
Window position                Max
---------------               -----
[1  3  -1] -3  5  3  6  7       <strong>3</strong>
 1 [3  -1  -3] 5  3  6  7       <strong>3</strong>
 1  3 [-1  -3  5] 3  6  7      <strong> 5</strong>
 1  3  -1 [-3  5  3] 6  7       <strong>5</strong>
 1  3  -1  -3 [5  3  6] 7       <strong>6</strong>
 1  3  -1  -3  5 [3  6  7]      <strong>7</strong>
</pre>

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

<pre>
<strong>Input:</strong> nums = [1], k = 1
<strong>Output:</strong> [1]
</pre>

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

<ul>
	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>4</sup> &lt;= nums[i] &lt;= 10<sup>4</sup></code></li>
	<li><code>1 &lt;= k &lt;= nums.length</code></li>
</ul>

class Solution {
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
        int n=nums.size();
        
        int maxi=-1e5;
        set<int>st; map<int,int>mp;
        vector<int>ans;
        
        for(int r=0;r<k;r++){
            maxi=max(maxi,nums[r]);
            st.insert(nums[r]); mp[nums[r]]++;
            // cout<<maxi<<endl;
        }
        // for(auto it:st){cout<<it<<" ";}
        // cout<<endl;
        int l=0,r=k-1;
        // cout<<l<<" "<<r<<endl;
        while(r<n)
        {
                // cout<<l<<" "<<r<<" "<<ans.size()<<endl;
                ans.push_back(maxi);
                mp[nums[l]]--; if(mp[nums[l]]==0){mp.erase(nums[l]);}
                // if(maxi==nums[l]){
                //     if(mp[nums[l]]==0){
                //         if(!st.empty())
                //         {auto it=st.end();
                //         it--;
                //         maxi=*it;}
                //         else{maxi=-1e5;}
                //     }
                    
                // }
                if(mp.empty()){maxi=-1e5;}
                // for(auto it:st){cout<<it<<" st ";}
                // cout<<endl;
                // cout<<maxi<<" "<<endl;
                l++; r++;
                if(r<n){
                    // maxi=max(maxi,nums[r]);
                    mp[nums[r]]++;
                    auto it=mp.end();
                    it--;
                    maxi=it->first;
                }
                // cout<<maxi<<" "<<endl;
           
        }
        return ans;
    }
};
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