239. Sliding Window Maximum

class Solution {
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
        priority_queue<pair<int, int>, vector<pair<int,int>>, less<pair<int,int>>> q;
        for(int i = 0; i < k; ++i) {
            q.push(pair(nums[i],i));
        }
        vector<int> ans;
        ans.push_back(q.top().first);
        for(int i = k; i < nums.size(); ++i) {
            q.push(pair(nums[i], i));
            auto t = q.top();
            while(t.second <= i - k) {
                q.pop();
                t = q.top();
            }
            ans.push_back(q.top().first);
        }
        return ans;
    }
};