代码随想录算法训练营20期|第五十一天|动态规划part12|309.最佳买卖股票时机含冷冻期 ● 714.买卖股票的最佳时机含手续费 ●总结

309.最佳买卖股票时机含冷冻期  

class Solution {
    public int maxProfit(int[] prices) {
        int n = prices.length;
        if (prices == null || prices.length == 0) return 0;
        int[][] dp = new int[prices.length][4];
        
        dp[0][0] = -prices[0];
        
        for (int i = 1; i < n; i++) {
            dp[i][0] = Math.max(dp[i - 1][0], Math.max(dp[i - 1][3] - prices[i], dp[i - 1][1] - prices[i]));
            dp[i][1] = Math.max(dp[i - 1][1], dp[i - 1][3]);
            dp[i][2] = dp[i - 1][0] + prices[i];
            dp[i][3] = dp[i - 1][2];
        }

        return Math.max(dp[n - 1][3], Math.max(dp[n - 1][1], dp[n - 1][2]));
    }
}

714.买卖股票的最佳时机含手续费  

class Solution {
    public int maxProfit(int[] prices, int fee) {
        int n = prices.length;
        int[][] dp = new int[n][2];
        dp[0][0] = -prices[0];
        for (int i = 1; i < n; i++) {
            dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] - prices[i]);
            dp[i][1] = Math.max(dp[i - 1][0] + prices[i] - fee, dp[i - 1][1]);
        }
        return Math.max(dp[n - 1][0], dp[n - 1][1]);
    }
}

• 总结