[Leetcode] Best Time to Buy and Sell Stock II (Java)

Say you have an array for which the ith element is the price of a given stock on day i.

Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock
before you buy again).

能进行多次操作，模拟一下就可以了

public class Solution {
public int maxProfit(int[] prices) {
int ret = 0;
int tmp = Integer.MAX_VALUE;
int buy = 0;
boolean flag = true;
for(int i=0;i<prices.length;i++){
if(flag){
if(prices[i]<tmp)
tmp=prices[i];
else if (prices[i]>tmp) {
buy = tmp;
tmp = prices[i];
flag = false;
}
}else {
if(prices[i]>tmp)
tmp = prices[i];
else if (prices[i]<tmp) {
ret+=tmp-buy;
tmp=prices[i];
flag = true;
}
}
}
if(!flag&&tmp>buy)
ret+=tmp-buy;
return ret;
}
}