<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) {
        vector<int> v1 ;
        // multiset<int> s1(nums.begin(), nums.begin() + k ); 
        // v1.push_back(*s1.rbegin()) ;

        // for ( int i = k ; i<nums.size() ; i++) { 
        //     auto itr = s1.find(nums[i-k]);
        //     s1.erase(itr) ;
        //     s1.insert(nums[i]) ;
        //     v1.push_back(*s1.rbegin()) ;

        // }
        priority_queue<int> pq(nums.begin(), nums.begin() + k ); 
        unordered_multiset s1(nums.begin() , nums.begin() + k) ;
        v1.push_back(pq.top()) ;
        for ( int i = k ; i<nums.size() ; i++) { 
            if ( nums[i-k] == pq.top() ) { pq.pop() ; }
            auto it = s1.find(nums[i-k]) ;
            s1.erase(it) ;
            pq.push(nums[i]) ;
            s1.insert(nums[i]) ;
            while ( s1.find(pq.top()) == s1.end()) { 
                pq.pop() ;
            }
            v1.push_back(pq.top()) ;
        }
        return v1 ;

        return v1 ;
            
        }

    
};
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