class Solution {
public:
    /**
     * 
     * @param prices int整型vector 
     * @return int整型
     */
    int maxProfit(vector<int>& prices) {
        // write code here
        int cur = 0, preMax = 0, numMax = 0;
        for(int i = 0; i < prices.size() - 1; i++)
        {
            cur = prices[i + 1] - prices[i]; // 用cur先分析相邻的情况
            preMax += cur;
            if (preMax < 0)
                preMax = 0; // 从零开始的异世界生活
            if (numMax < preMax)
                numMax = preMax;
        }
        return numMax;
    }
};