LeetCode 滑动窗口最大值

 1 class Solution {
 2 public:
 3     vector<int> maxSlidingWindow(vector<int>& nums, int k) {
 4         vector< int > ans;
 5         deque< int > DQ;
 6         
 7         if(nums.empty()) return ans;
 8         for(int i = 0; i <= k - 1; ++i) {
 9             while(!DQ.empty() && nums[i] > nums[DQ.back()]) DQ.pop_back();
10             DQ.push_back(i);
11         }
12         
13         ans.push_back(nums[DQ.front()]);
14         for(int i = k; i < (int)nums.size(); ++i) {
15             if(i - k == DQ.front()) DQ.pop_front();
16             while(!DQ.empty() && nums[i] > nums[DQ.back()]) DQ.pop_back();
17             DQ.push_back(i);
18             ans.push_back(nums[DQ.front()]);
19         }
20         
21         return ans;
22     }
23 };