/**
knakul853
**/
class Solution {
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {

        int n = (int)nums.size();
        deque<int>dq;
        vector<int>ans;
        int i;

        for(i=0;i<n;i++)
        {
            if( !dq.empty() && dq.front() == i-k )dq.pop_front();

            while( !dq.empty() && nums[dq.back()] < nums[i] ){ dq.pop_back();}

            dq.push_back(i);

            if(i >= k-1){
                ans.push_back(nums[dq.front()]);
            }
        }


        return ans;

    }
};