Best Time to Buy and Sell Stock with Cooldown

 1 public class Solution {
 2     public int maxProfit(int[] prices) {
 3         int lastBuy = 0, lastSell = 0, buy = Integer.MIN_VALUE, sell = 0;
 4         for (int i = 0; i < prices.length; i++) {
 5             lastBuy = buy;
 6             buy = Math.max(buy, lastSell - prices[i]);
 7             
 8             lastSell = sell;
 9             sell = Math.max(sell, lastBuy + prices[i]);
10         }
11         return sell;
12     }
13 }