Untitled

class Solution {
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
        vector<int>ans;
        deque<int>dq;
        for(int i = 0; i < nums.size(); 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;
    }
};