# Best Time to Buy and Sell Stock IV

## Desicription

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.

Note: You may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

Example 1:

```Input: [2,4,1], k = 2
Output: 2
Explanation: Buy on day 1 (price = 2) and sell on day 2 (price = 4), profit = 4-2 = 2.```

Example 2:

```Input: [3,2,6,5,0,3], k = 2
Output: 7
Explanation: Buy on day 2 (price = 2) and sell on day 3 (price = 6), profit = 6-2 = 4.
Then buy on day 5 (price = 0) and sell on day 6 (price = 3), profit = 3-0 = 3.```

## Solution

```class Solution {
public:
int maxProfit(int k, vector<int>& prices) {
priority_queue<int> profits;
stack<pair<int, int>> vps;
int v = 0;
int p = 0;
int len = prices.size();
while(p < len) {
for(v = p; v < len-1 && prices[v] >= prices[v+1]; v++);
for(p = v+1; p < len && prices[p] >= prices[p-1]; p++);
while(vps.size() && prices[vps.top().first] > prices[v]) {
profits.push(prices[vps.top().second - 1] - prices[vps.top().first]);
vps.pop();
}
while(vps.size() && prices[vps.top().second-1] <= prices[p-1]) {
profits.push(prices[vps.top().second-1] - prices[v]);
v = vps.top().first;
vps.pop();
}
vps.push(pair<int, int>(v, p));
}
while(vps.size()) {
profits.push(prices[vps.top().second-1] - prices[vps.top().first]);
vps.pop();
}
int res = 0;
while(k-- && profits.size())
res += profits.top(), profits.pop();
return res;
}
};```

0 条评论

• ### Leetcode 188 Best Time to Buy and Sell Stock IV

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

• ### Array - 188. Best Time to Buy and Sell Stock IV

Say you have an array for which the _i_th element is the price of a given stock ...

• ### 【leetcode】Best Time to Buy and Sell Stock

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

• ### Leetcode: Best Time to Buy and Sell Stock

题目： Say you have an array for which the ith element is the price of a given st...

• ### LeetCode 121 Best Time to Buy and Sell Stock

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

• ### Leetcode 121 Best Time to Buy and Sell Stock

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

• ### leetcode-121-Best Time to Buy and Sell Stock

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

• ### Leetcode 121. Best Time to Buy and Sell Stock

版权声明：博客文章都是作者辛苦整理的，转载请注明出处，谢谢！ https://blog.csdn....

• ### 【leetcode】Best Time to Buy and Sell Stock II

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

• ### 【leetcode】Best Time to Buy and Sell Stock III

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

• ### Leetcode: Best Time to Buy and Sell Stock II

题目： Say you have an array for which the ith element is the price of a given st...

• ### LeetCode 0121 - Best Time to Buy and Sell Stock

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

• ### 一个函数解决【LeetCode 买卖股票的最佳时机】系列所有题目！

之前介绍了【LeetCode 买卖股票的最佳时机】系列一共六道题目，这里把之前的题解还有题目链接汇总一下，方便大家查找。

• ### LeetCode 188. Best Time to Buy and Sell Stock IV (动态规划)

题意：给你一个数组代表每天的股价。你有k次买入和卖出的机会，问你最多能赚多少钱。买入之前必须卖出已有股份。同一天是可以先买，再卖，或者先卖再买的。

### Reck Zhang

TencentGame Developer

Tencent · Game Developer (已认证)