求教这个弗洛伊德算法求最短路径的程序哪里错了。
自己测试了几组数据都没错。。但是判题的有的数据过不去，也不知道是什么数据


#include<stdio.h>

int n;
int D[100][100];
int area[100][100];
int street[100][100][100];

void floyd()
{
    int a,b,c;
    int i,j,k;
    int sum;
    for(k=0;k<n;k++)
        for(i=0;i<n;i++)
            for(j=0;j<n;j++)
            {
                sum=D[i][k]+D[k][j];
                if(sum<D[i][j])
                {
                    D[i][j]=sum;
                    for(a=0;;a++)
                    {
                        if(street[i][k][a]==-1)
                        break;
                    }
                    for(b=0;b<a-1;b++)
                    {
                        street[i][j][b]=street[i][k][b];
                    }
                    for(a=0;;b++,a++)
                    {
                        if(street[k][j][a]==-1) break;
                        street[i][j][b]=street[k][j][a];
                    }
                }
            }
}

int main()
{
    int m;
    int a,b,c;
    int StartNode,EndNode;
    scanf("%d",&n);
    for(a=0;a<n;a++)
        for(b=0;b<n;b++)
            for(c=0;c<100;c++)
            {
                street[a][b][c]=-1;
            }
    for(a=0;a<n;a++)
        for(b=0;b<n;b++)
        {
            street[a][b][0]=a;
            street[a][b][1]=b;
        }
    for(a=0;a<n;a++)
        for(b=0;b<n;b++)
        {
            scanf("%d",&area[a][b]);
        }
    for(a=0;a<n;a++)
        for(b=0;b<n;b++)
        {
            D[a][b]=area[a][b];
        }
    floyd();

    scanf("%d",&m);
    for(a=0;a<m;a++)
    {
        scanf("%d%d",&StartNode,&EndNode);
        for(b=0;;b++)
        {
            if(street[StartNode][EndNode][b]==-1) break;
            printf("%d\n",street[StartNode][EndNode][b]);
        }
    }

    return 0;
}