答案

public class Solution {
    public int maxProfit(int[] prices) {
        if(prices==null||prices.length<=1)
        {
            return 0;
        }
        int buyPrice=prices[0];
        int profit=0;
        int LEN=prices.length;
        for(int i=1;i<LEN;i++){
            if(prices[i]>buyPrice)
            {
                profit+=prices[i]-buyPrice;
            }
            buyPrice=prices[i];
        }
        return profit;
    }
}