LeetCode 239. 滑动窗口最大值

class Solution {
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
        deque<int> q;
        vector<int> res;
        for(int i=0;i<nums.size();i++)
        {
            //删除滑出窗口的元素
            while(q.size()&&i-q.front()>=k)    q.pop_front();
            //插入新元素
            while(q.size()&&nums[q.back()]<=nums[i])
                q.pop_back();
            q.push_back(i);
            if(i>=k-1)
                res.push_back(nums[q.front()]);
        }
        return res;
    }
};