suffix array

#include 
#include 
char num[4001];
int suffix[4001];
int mark[4001];

int comparel(char* a, char*b)
{
    int i;
    for(i = 0; a[i] !=0 && b[i] != 0; i++)
    {
        if(a[i] != b[i] )
            return i;
    }
    return i;
}
int compare(char *a, char* b)
{
    int i;
    for(i = 0; a[i] != 0 && b[i] != 0; i++)
    {
        if(a[i] > b[i] )
            return 1;
        else if(a[i] == b[i])
            continue;
        else
            return -1;
    }
    if(a[i] == 0 && b[i] != 0)
        return 1;
    else if(a[i] != 0 && b[i] == 0)
        return -1;
    return 0;
}

void removel(int len)
{
    int i, j,tmp;
    for(i = 0,j = i+1; j < len; i++,j++)
    {
        tmp = comparel(num+ (len-suffix[i]), num+ (len-suffix[j]));
        if(tmp==0)
            continue;
        else
            mark[j] += tmp;
    }
}

void getparse(int len)
{
    int i, j,tmp;
    for(i = 0; i < len; i++)
    {
        for(j = i+1; j < len; j++)
        {
            if (compare(num+ (len-suffix[i]), num+ (len - suffix[j])) > 0)
            {
                tmp = suffix[i];
                suffix[i] = suffix[j];
                suffix[j] = tmp;
            }
        }
    }
}

int main(void)
{
    int T, test_case;
    int len, i,j,K;

    setbuf(stdout, NULL);

    scanf("%d", &T);
    for(test_case = 0; test_case < T; test_case++)
    {
        scanf("%d", &K);
        scanf("%s", num);
        memset(mark, 0, sizeof(mark));
        len = strlen(num);
        for(i = 0; i < len; i ++)
        {
            suffix[i] = len - i;
        }
        getparse(len);
        removel(len);
        for(i = 0; i < len; i++)
        {
            if(K > suffix[i]-mark[i])
                K -= suffix[i]-mark[i];
            else
            {
                    printf("Case #%d\n", test_case+1);
                    for(j = (len-suffix[i]); j < len-suffix[i]+mark[i]+K; j++)
                    {
                        printf("%c", num[j]);
                        if(j == len-suffix[i]+mark[i]+K-1)
                            printf("\n");
                    }
                    K -= suffix[i]-mark[i];
                    break;
                }
            }

            if(K > 0)
            {
                printf("Case #%d\n", test_case+1);
                printf("%s\n", "none");
            }

        }


    return 0;//Your program should return 0 on normal termination.
}