class Solution {
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
     int n = nums.size();
        if (n == 0 || k == 0) return {};

        vector<int> v(n-k+1);
        deque<int> d;

        for (int i = 0; i < n; ++i) {
            while (!d.empty() && d.front() <= i-k)
            d.pop_front();

            while (!d.empty() && nums[d.back()] < nums[i])
            d.pop_back();

            d.push_back(i);

            if (i >= k-1)
            v[i+1-k] = nums[d.front()];
        }
        return v;
    }

};