HOOJ1231为什么运行不正确....

/*

 *x1 -x2 x3 -x4(xi全为正数)

 *判断 x3是否要加入 到{x1, -x2, x3}序列中的标准为 x2<=x3成立

 *否则  不加入 就表示 序列在-x2此处断开

 */
#include <stdio.h>
#include <math.h>

#define MAX_SIZE 10000

struct node
{
    int sum;//存放最大和
    int first_site;//存放第一个元数的下标值
    int end_site;//存放最后一个元数的下标值
};

int main()
{
    int num;//存放待要输入整数的个数
    int a[MAX_SIZE];//存放输入整数 的数组
    int i = 0;
    int temp = 0;
    struct node num_1, num_2;

    while( scanf("%d", &num) )
    {
        if( num == 0 )
        {//为零时， 输入结束，不用做处理
            printf("0 0 0\n");
            continue;
        }
        for( i=0; i<num; ++i )
        {//录取num个整数到数组a中
            scanf("%d", &a[i]);
        }
        num_1.sum = 0; num_1.end_site = 0; num_1.first_site = 0;//存最终结果
        num_2.sum = 0; num_2.end_site = 0; num_2.first_site = 0;//临时存放中间结果
        i = 0;
        while( i != num )
        {
            if( a[i] > 0 )
            {
                num_2.sum = 0;
                num_2.sum = +a[i];
                num_2.first_site = i;
                ++i;
loop:
                while( i!=num && a[i]>0 )
                {
                    num_2.sum += a[i];
                    ++i;
                }

                if( i == num )
                {
                    num_2.end_site = i-1;
                    if( num_1.sum<num_2.sum )
                    {
                        num_1.sum = num_2.sum;
                        num_1.first_site = num_2.first_site;
                        num_1.end_site = num_2.end_site;
                    }
                }
                else
                {   
                    num_2.end_site = i-1;
                    temp = 0;
                    while( i!=num && a[i]<=0 )
                    {
                        temp += a[i];
                        ++i;
                    }
                    if( i==num && num_1.sum<num_2.sum )
                    {
                        num_1.sum = num_2.sum;
                        num_1.first_site = num_2.first_site;
                        num_1.end_site = num_2.end_site;
                    }
                    else
                    {
                        if( abs(temp)>a[i] && num_1.sum<num_2.sum )
                        {
                            num_1.sum = num_2.sum;
                            num_1.first_site = num_2.first_site;
                            num_1.end_site = num_2.end_site;
                        }
                        else
                        {
                            num_2.sum += temp;
                            goto loop;
                        }
                    }
                }

            }
            else
            {
                ++i;
            }
        }
        if( num_1.sum == 0 )
        {
            num_1.end_site = num-1;
            num_1.first_site = 0;
        }
        printf("%d %d %d\n", num_1.sum, a[num_1.first_site], a[num_1.end_site] );
    }

    return 0;
}