力扣-901题 股票价格跨度（C++）- 单调栈

题目链接：https://leetcode.cn/problems/online-stock-span/
题目如下：

class StockSpanner {
public:
    StockSpanner() {

    }
    
    int next(int price) {
        //求的是左边第一个比当前值大的数的位置
        //使用单调栈，只不过单调栈要同时存储price和当前price的跨度
        
        pair<int,int> cur(price,1);    

        while(stk.size()!=0&&stk.top().first<=price){
            cur.second+=stk.top().second;
            stk.pop();
        }
        stk.push(cur);

        return cur.second;
    }
private:
    stack<pair<int, int>> stk;
};

/**
 * Your StockSpanner object will be instantiated and called as such:
 * StockSpanner* obj = new StockSpanner();
 * int param_1 = obj->next(price);
 */