<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 start=0;
        // int end=0;
        // int n = nums.size();
        // vector<int> res;
        // set<int> st;
        // int sum=0;
        // while(end<n)
        // {
        //     st.insert(nums[end]);
        //     if((end-start+1)<k)
        //     {
                
        //         end++;
        //     }

            

        //     else if((end-start+1)==k)
        //     {
                
                
                
        //         res.push_back(*st.rbegin());
        //         st.clear();
        //         start++;
                
        //         end++;
        //     }
            
        // }
        // return res;

        vector<int> res;
        set<int> st;
        unordered_map<int, int> count; // Map to keep track of element counts

        for (int end = 0; end < nums.size(); ++end) {
            st.insert(nums[end]);
            count[nums[end]]++;

            // Remove the element that is sliding out of the window
            if (end >= k - 1) {
                // Add the maximum element to the result
                res.push_back(*st.rbegin());

                int start = end - k + 1;
                count[nums[start]]--;
                if (count[nums[start]] == 0) {
                    st.erase(nums[start]);
                    count.erase(nums[start]);
                }
            }
        }

        return res;
    }
};
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