123.best-time-to-buy-and-sell-stock-iii.java

/*
 * @lc app=leetcode id=123 lang=java
 *
 * [123] Best Time to Buy and Sell Stock III
 */

// @lc code=start
class Solution {
    public int maxProfit(int[] prices) {
        int n = prices.length;
        if (n == 0) {
            return 0;
        }
        
        int maxK = 2;
        int[][][] dp = new int[n][maxK + 1][2];

        for (int i = 0; i < prices.length; i++) {
            for (int k = maxK; k >= 1; k--) {
                if (i - 1 == -1) {
                    dp[i][k][0] = 0;
                    dp[i][k][1] = -prices[i];
                    continue;
                }
                dp[i][k][0] = Math.max(dp[i - 1][k][0], dp[i - 1][k][1] + prices[i]);
                dp[i][k][1] = Math.max(dp[i - 1][k][1], dp[i - 1][k - 1][0] - prices[i]);
            }
        }
        
        return dp[n - 1][maxK][0];
    }
}
// @lc code=end