俺的代码。
#include<iostream>
#include<stdio.h>
using namespace std;
//=============================================================
int p[100005];
#define M -1001;
int maxsum=M;
int sum1[100005];int sum2[100005];
int main()
{
	long long n;
	int max=M;
	while(cin>>n&&n)
	{
		memset(p,0,sizeof(p));
		memset(sum1,0,sizeof(sum1));
		memset(sum2,0,sizeof(sum2));

		scanf("%d",&p[0]);
		sum1[0]=p[0];

		for(int i=1;i<n;++i)
		{
			scanf("%d",&p[i]);
			if(sum1[i-1]>0)
			{
				sum1[i]=sum1[i-1]+p[i];
			}
			else
			{
				sum1[i]=p[i];
			}
			//if(sum1[i]>max)max=sum1[i];
		}

		int m=M;
		sum2[n-1]=p[n-1];
		for(int i=n-1;i>=1;--i)
		{
			if(sum2[i]>0)
			{
				sum2[i-1]=sum2[i]+p[i-1];
			}
			else
			{
				sum2[i-1]=p[i-1];
			}
			if(sum2[i]>m)m=sum2[i];
			
			if(m+sum1[i-1]>maxsum)
			{
				maxsum=m+sum1[i-1];
			}
		}
		printf("%d\n",maxsum);

		
	}
}