class Solution {
public:
    /**
     * 
     * @param prices int整型vector 
     * @return int整型
     */
    int maxProfit(vector<int>& prices) {
        // write code here
        //局部最优解
        int value = 0;
        int min = prices[0];
        int minIndex = 0;
        int max = prices[0];
        int maxIndex = 0;
        int i = 0;
        while (i<prices.size())
        {
            if (prices[i]>max)
            {
                max = prices[i];
                maxIndex = i;
            }
            if (prices[i]<min)
            {
                min = prices[i];
                minIndex = i;
                max = 0;
            }
            if (maxIndex>minIndex)
            {
                value = value>(max-min)?value:(max-min);
            }
            i++;
        }
        return value;
    }
};