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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 at most k transactions.
解题思路：
本题是Best Time to Buy and Sell Stock系列最难的一道，需要用到dp，JAVA实现如下：
public int maxProfit(int k, int[] prices) {
if (k == 0 || prices.length < 2)
return 0;
if (k > prices.length / 2) {
int maxProfitII = 0;
for (int i = 1; i < prices.length; ++i)
if (prices[i] > prices[i - 1])
maxProfitII += prices[i] - prices[i - 1];
return maxProfitII;
}
int[] buy=new int[k];
int[] sell=new int[k];
for(int i=0;i<buy.length;i++)
buy[i]=Integer.MIN_VALUE;
for (int i = 0; i < prices.length; i++)
for (int j = k - 1; j >= 0; j--) {
sell[j] = Math.max(sell[j], buy[j] + prices[i]);
if (j == 0)
buy[j] = Math.max(buy[j], -prices[i]);
else
buy[j] = Math.max(buy[j], sell[j - 1] - prices[i]);
}
return sell[k - 1];
}
Java for LeetCode 188 Best Time to Buy and Sell Stock IV【HARD】
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原文地址：http://www.cnblogs.com/tonyluis/p/4557321.html
