题解 | 买卖股票的最好时机(三)

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别


        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();

            int[] prices = new int[a];
            for (int i = 0; i < a; i++) {
                prices[i] = in.nextInt();
            }
            int[][] data = new int[3][prices.length];
            for (int i = 1; i <= 2; i++) {
                int max = 0;
                for (int j = 0; j < prices.length; j++) {
                    if (j == 0) {
                        max =  -prices[0];
                        data[i][0] = 0;
                    } else {
                        max = Math.max(max, data[i - 1][j - 1] - prices[j]);
                        data[i][j] = Math.max(data[i][j - 1], prices[j] + max );
                    }

                }
            }
            System.out.println(data[2][prices.length - 1]);
        }


    }
}