解法一：贪心

如果加上当前数小于0，那么不如不加，从头开始；否则就有继续增长的可能，继续加并更新最大值。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        final int n = Integer.parseInt(reader.readLine());
        String[] strs = reader.readLine().split(" ");
        int max = 0;
        int sum = 0;
        for (int i = 0, num; i < n; ++i) {
            num = Integer.parseInt(strs[i]);
            if (sum + num < 0) {
                sum = 0;
            } else {
                sum += num;
                max = Math.max(max, sum);
            }
        }
        System.out.println(max);
    }
}