#include <cstdio>
class Solution {
public:
    /**
     * 
     * @param prices int整型vector 
     * @return int整型
     */
    int maxProfit(vector<int>& prices) {
        // write code here
        int min = prices[0];
        int max = prices[0];
        int i = 0;
        int value = 0;
        while (i < prices.size()) 
        {
            if (prices[i]>max)
            {
                max = prices[i];
            }
            if (prices[i]<min)
            {
                min = prices[i];
            }
            if (max == prices[i]&&i+1>=prices.size())
            {
                value+=max-min;
            }
            else if (max == prices[i]&&prices[i+1]<prices[i])  
            {
                value+=max-min;
                max = prices[i+1];
                min = prices[i+1];
            }
            i++;
        }
        return value;
    }
};