[Leetcode239] 力扣239：滑动窗口的最大值

class Solution {
    
    
public:
    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
    
    
        int n = nums.size();
        deque<int> q;
        vector<int> res;
        for (int i = 0; i < k; ++i) {
    
    
            while (!q.empty() && nums[i] >= nums[q.back()]) q.pop_back();
            q.push_back(i);
        }
        res.push_back(nums[q.front()]);
        for (int i = k; i < n; ++i) {
    
    
            while (!q.empty() && nums[i] >= nums[q.back()]) q.pop_back();
            q.push_back(i);
            while (q.front() < i - k +1) q.pop_front();
            res.push_back(nums[q.front()]);
        }
        return res;
    }
};