动态规划31（Leetcode188买卖股票的最佳时机4）

从月亮走向月亮72023-11-11 17:39

代码：

我的状态方程：

buy[i][j]=max{buy[i−1][j],sell[i−1][j-1]−price[i]}

题解里的：

buy[i][j]=max{buy[i−1][j],sell[i−1][j]−price[i]}

..没理解题解的但我的通过了

java 复制代码

class Solution {
    public int maxProfit(int k, int[] prices) {
        if(prices.length==0)return 0;
        int n = prices.length;
        k = Math.min(k,n/2);
        if(k==0)return 0;
        int[][] buy = new int[n][k];
        int[][] sell = new int[n][k];
        buy[0][0]=-prices[0];
        sell[0][0]=0;
        for(int i=1;i<k;i++){
            buy[0][i] = sell[0][i] = Integer.MIN_VALUE / 2;
        }
        for(int i=1;i<n;i++){
            buy[i][0] = Math.max(buy[i-1][0],-prices[i]);
            sell[i][0] = Math.max(sell[i-1][0],buy[i-1][0]+prices[i]);
            for(int j=1;j<k;j++){
                buy[i][j] = Math.max(sell[i-1][j-1]-prices[i],buy[i-1][j]);
                sell[i][j] = Math.max(buy[i-1][j]+prices[i],sell[i-1][j]);
            }
        }
        return Arrays.stream(sell[n-1]).max().getAsInt();
    }
}