Problem link [leetcode.com]
I don't know what to write so here's my recently accepted Leetcode submission:

class Solution {
⠀⠀⠀public int maxProfit(int k, int[] prices) {
⠀⠀⠀⠀⠀⠀int len = prices.length;
⠀⠀⠀⠀⠀⠀int[][] dp = new int[len + 1][2 * k + 1];
⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀for (int j = 1; j <= 2 * k; j++) {
⠀⠀⠀⠀⠀⠀⠀⠀⠀for (int i = j; i <= len; i++) {
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀int multiplier = j % 2 == 0 ? 1 : -1;
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀int product = multiplier * prices[i - 1];
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀if (i == j) {
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀dp[i][j] = product + dp[i - 1][j - 1];
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀} else {
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀dp[i][j] = Math.max(
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀dp[i - 1][j], product + dp[i - 1][j - 1]);
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀}
⠀⠀⠀⠀⠀⠀⠀⠀⠀}
⠀⠀⠀⠀⠀⠀}

⠀⠀⠀⠀⠀⠀int result = 0;
⠀⠀⠀⠀⠀⠀for (int i = 2; i <= 2 * k; i += 2)
⠀⠀⠀⠀⠀⠀⠀⠀⠀result = Math.max(result, dp[len][i]);
⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀return result;
⠀⠀⠀}
}