LeetCode-in-Java

188. Best Time to Buy and Sell Stock IV

Hard

You are given an integer array prices where prices[i] is the price of a given stock on the ith day, and an integer k.

Find the maximum profit you can achieve. You may complete at most k transactions.

Note: You may not engage in multiple transactions simultaneously (i.e., you must sell the stock before you buy again).

Example 1:

Input: k = 2, prices = [2,4,1]

Output: 2

Explanation: Buy on day 1 (price = 2) and sell on day 2 (price = 4), profit = 4-2 = 2.

Example 2:

Input: k = 2, prices = [3,2,6,5,0,3]

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.

Constraints:

• 0 <= k <= 100
• 0 <= prices.length <= 1000
• 0 <= prices[i] <= 1000

Solution

public class Solution {
    public int maxProfit(int k, int[] prices) {
        int n = prices.length;
        int[] dp = new int[k + 1];
        int[] maxdp = new int[k + 1];
        for (int i = 0; i <= k; i++) {
            maxdp[i] = Integer.MIN_VALUE;
        }
        for (int i = 1; i <= n; i++) {
            maxdp[0] = Math.max(maxdp[0], dp[0] - prices[i - 1]);
            for (int j = k; j >= 1; j--) {
                maxdp[j] = Math.max(maxdp[j], dp[j] - prices[i - 1]);
                dp[j] = Math.max(maxdp[j - 1] + prices[i - 1], dp[j]);
            }
        }
        return dp[k];
    }
}

This site is open source. Improve this page.