面试题59：滑动窗口的最大值

即求队列的最大值

#include <queue>

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