一、题目内容

二、题解

解法1：

思路

代码

public class Solution {
    public int maxProfit (int[] prices) {
        // write code here
        if(prices == null||prices.length<2){
            return 0;
        }
        int len = prices.length;
        int buy1 = -prices[0],sell1 = 0;
        int buy2 = -prices[0],sell2 = 0;
        for(int i = 1;i<len;i++){
            buy1 = Math.max(buy1,-prices[i]);
            sell1 = Math.max(sell1, buy1+prices[i]);
            buy2 = Math.max(buy2,sell1-prices[i]);
            sell2 = Math.max(sell2, buy2+prices[i]);
        }
        return sell2;
    }
}