Problem:
Maximum Sum Sequence

Given a sequence of numbers a1, a2, a3, ..., an, find the maximum sum of a contiguous subsequence of those numbers. Note that, a subsequence of one element is also a contiquous subsequence.

Input

The input consists of multiple datasets. Each data set consists of:

n
a1
a2
.
.
an

You can assume that 1 ≤ n ≤ 5000 and -100000 ≤ ai ≤ 100000.

The input end with a line consisting of a single 0.

Output

For each dataset, print the maximum sum in a line.

Sample Input

7
-5
-1
6
4
9
-6
-7
13
1
2
3
2
-2
-1
1
2
3
2
1
-2
1
3
1000
-200
201
0

Output for the Sample Input

19
14
1001

Solution in JAVA (judge verdict: Wrong Answer)

import java.io.*;
import java.util.*;
class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int num=Integer.parseInt(br.readLine());
        if(num==0) System.exit(0);
        while(true){
            boolean end_flag=false;
            int[] array=new int[num];
            for(int i=0;i<num;i++){
                array[i]=Integer.parseInt(br.readLine());
            }int i=0;
            long sum=0;
            while(i<array.length&&array[i]<0) i++;
            if(i==array.length) end_flag=true;
            while(i<array.length&&!end_flag){
                long minus_sum=0;
                long plus_sum=0;
                while(i<array.length&&array[i]<0){
                    minus_sum+=array[i];
                    i++;
                }while(i<array.length&&array[i]>=0){
                    plus_sum+=array[i];
                    i++;
                }if(plus_sum>(-minus_sum)) sum+=(plus_sum+minus_sum);
            }if(end_flag){
                Arrays.sort(array);
                System.out.println(array[array.length-1]);
            }else System.out.println(sum);
            num=Integer.parseInt(br.readLine());
            if(num==0) System.exit(0);
        }
    }
}