题解 | #买卖股票的最好时机(二)#

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
        int n = in.nextInt();
        int[] prices = new int[n];
        int[] delta = new int[n];
        for(int i = 0;i < n;i++){
            prices[i] = in.nextInt();
        }
        delta[0] = 0;
        for(int i = 1;i < n;i++){
            delta[i] = prices[i] - prices[i-1];
        }
        int[] dp = new int[n];
        dp[0] = 0;
        for(int i = 1;i < n;i++){
            dp[i] = Math.max(dp[i-1] + delta[i], delta[i]);
        }
        int result = 0;
        for(int i = 1;i < n;i++){
            if(0 < delta[i]){
                result += delta[i];
            }
        }
        System.out.print(result);
    }
}