滑动窗口的最大值

class Solution {
public:
    vector<int> maxInWindows(const vector<int>& num, unsigned int size)
    {
        deque<int> dep;
        vector<int> rev;
        for(int i=0;i<num.size();i++)
        {
            while(dep.size()&&num[dep.back()]<=num[i])
            {
                dep.pop_back();
            }
            if(dep.size()&&(i-dep.front()+1)>size)
                dep.pop_front();
            dep.push_back(i);
            if(size&&i+1>=size)
                rev.push_back(num[dep.front()]);
        }
        return rev;
    }
};