b.c

#include <stdio.h>

int main()
{
  unsigned long int  i, temp, base;
  unsigned char j, k;
  unsigned char count[10];

  for( i = 1e9; i < 1e10; i++ ) 
  {
    memset(count, 1, 10);
    base = 1e9;
    temp = i;
    for( j = 0; j < 10; j++ ) 
    {
      k = temp / base;
      temp = temp % base;
      base = base / 10;
      count[k]++;
      if ( count[k] > 9 ) {
        goto failed;
      }
    }
    base = 1e9;
    temp = i;
    for( j = 0; j < 10; j++ ) 
    {
      k = temp / base;
      temp = temp % base;
      base = base / 10;
      if ( k == count[j] ) 
      {
        if (j == 9) 
        {
          printf("succeeded: %010u\n", i);
        }
      } 
      else 
      {
        goto failed;
      }
    }
    failed:;
    // printf("tested: %010u\n", i);
  }

  return 0;
}