FZU 1914 Funny Positive Sequence

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
#define LL long long
LL a[500001];
bool flag[500001];
int main()
{
    int t,n,i,total,id=1;
    LL sum;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);
        memset(flag,0,sizeof(flag));
        total=n;
        for(i=0;i<n;i++)
            scanf("%I64d",&a[i]);
        sum=a[n-1];
        if(sum<=0)
        {
            total--;
            flag[n-1]=1;
        }
        for(i=n-2;i>=0;i--)
        {
            if(sum<=0)
            {
                sum+=a[i];
                if(sum<=0)
                {
                    total--;
                    flag[i]=1;
                }
            }
            else
            {
                if(a[i]<=0)
                {
                    sum=a[i];
                    total--;
                    flag[i]=1;
                }
            }
        }
        if(sum<=0)
        {
            for(i=n-1;i>=0;i--)
            {
                sum+=a[i];
                if(sum<=0 && flag[i]==0)
                    total--;
                if(sum>0)
                    break;
            }
        }
        printf("Case %d: %d\n",id++,total);
    }
    return 0;
}