Day42 ＞＞ 188、买卖股票的最佳时机IV + 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

想逃离铁厂的老铁2026-01-18 13:34

188、买卖股票的最佳时机IV

java 复制代码

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

309.最佳买卖股票时机含冷冻期

java 复制代码

class Solution {
    public int maxProfit(int[] prices) {
        if (prices == null || prices.length < 2) {
            return 0;
        }
        int[][] dp = new int[prices.length][2];

        dp[0][0] = 0;
        dp[0][1] = -prices[0];
        dp[1][0] = Math.max(dp[0][0], dp[0][1] + prices[1]);
        dp[1][1] = Math.max(dp[0][1], -prices[1]);

        for (int i = 2; i < prices.length; i++) {
            dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1] + prices[i]);
            dp[i][1] = Math.max(dp[i - 1][1], dp[i - 2][0] - prices[i]);
        }
        return dp[prices.length - 1][0];
    }
}

714.买卖股票的最佳时机含手续费

java 复制代码

class Solution {
    public int maxProfit(int[] prices, int fee) {
        int dp[][] = new int[2][2];
        int len = prices.length;
        dp[0][0] = -prices[0];

        for(int i = 1; i < len; i++){
            dp[i % 2][0] = Math.max(dp[(i - 1) % 2][0], dp[(i - 1) % 2][1] - prices[i]);
            dp[i % 2][1] = Math.max(dp[(i - 1) % 2][1], dp[(i - 1) % 2][0] + prices[i] - fee);
        }

        return dp[(len - 1) % 2][1];
    }
}