tkcn

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>

#define BUF_SIZE (1<<16)
#define LIST_LEN (1024*1024*38)
#define WORD_LEN (16)

#define TIMES (1000*9900)

char buf[BUF_SIZE];
char* p_buf = buf;

void static inline flush() {
   write(1, buf, p_buf-buf);
   p_buf = buf;
}

void static inline print(char* s) {
   while (*s!='\0') *(p_buf++) = *(s++);
   if (p_buf-buf>BUF_SIZE-100) flush();
}

int main(int argc, const char *argv[])
{
   struct timeval start;
   struct timeval now;
   gettimeofday(&start, NULL);

   char rot[] = {'0', '1', '6', '8', '9'};
   char rrot[] = {'0', '1', '9', '8', '6'};
   char* sym[] = {"0", "1", "8"};
   int idx[] = {4, 0};
   char (*list)[2][LIST_LEN][WORD_LEN] = malloc(4L*LIST_LEN*WORD_LEN);
   strcpy(list[0][0][0], "1");
   strcpy(list[0][0][1], "6");
   strcpy(list[0][0][2], "8");
   strcpy(list[0][0][3], "9");
   strcpy(list[0][1][0], "1\n");
   strcpy(list[0][1][1], "9\n");
   strcpy(list[0][1][2], "8\n");
   strcpy(list[0][1][3], "6\n");

   print("0\n1\n8\n");
   int b = 0;
   for (int i=0;i<idx[b];i++) {
       print(list[b][0][i]);
       print(list[b][1][i]);
   }
   for (int i=0;i<idx[b];i++) {
       for (int j=0;j<3;j++) {
           print(list[b][0][i]);
           print(sym[j]);
           print(list[b][1][i]);
       }
   }
   int timesup = 0;
   for (int l=2;l<20;l++) {
       if (timesup) break;
       int nb = b^1;
       int idxb = idx[b];
       int idxnb = 0;
       for (int i=0;i<idxb;i++) {
           for (int j=0;j<5;j++) {
               strcpy(list[nb][0][idxnb], list[b][0][i]);
               list[nb][0][idxnb][l-1] = rot[j];

               list[nb][1][idxnb][0] = rrot[j];
               strcpy(list[nb][1][idxnb]+1, list[b][1][i]);

               print(list[nb][0][idxnb]);
               print(list[nb][1][idxnb]);

               idxnb++;
           }
           if ((i+1)%10000==0) {
               gettimeofday(&now, NULL);
               if ((now.tv_sec-start.tv_sec)*1000000+(now.tv_usec-start.tv_usec)>TIMES) {
                   timesup = 1;
                   break;
               }
           }
       }
       if (timesup) break;
       for (int i=0;i<idxnb;i++) {
           for (int j=0;j<3;j++) {
               print(list[nb][0][i]);
               print(sym[j]);
               print(list[nb][1][i]);
           }
           if ((i+1)%10000==0) {
               gettimeofday(&now, NULL);
               if ((now.tv_sec-start.tv_sec)*1000000+(now.tv_usec-start.tv_usec)>TIMES) {
                   timesup = 1;
                   break;
               }
           }
       }
       idx[nb] = idxnb;
       b ^= 1;
   }
   flush();
   return 0;
}