My code

… was written in C++11 and can be compiled with G++, Clang++, Visual C++. You can download it, too. Or just jump to my GitHub repository.

       
#include <set>
       
#include <iostream>
       
#include <algorithm>
       
 
       
int main()
       
{
       
  // precomputation step 1:
       
  // find all primes below sqrt(987654321)
       
  std::set<unsigned int> smallPrimes;
       
  smallPrimes.insert(2);
       
  for (unsigned int i = 3; i*i <= 987654321; i += 2)
       
  {
       
    bool isPrime = true;
       
    for (auto p : smallPrimes)
       
    {
       
      // abort, no divisors possible
       
      if (p*p > i)
       
        break;
       
 
       
      // divisor found ?
       
      if (i % p == 0)
       
      {
       
        isPrime = false;
       
        break;
       
      }
       
    }
       
 
       
    // found a prime number
       
    if (isPrime)
       
      smallPrimes.insert(i);
       
  }
       
 
       
  // precomputation step 2:
       
  // generate all permutations of the strings "12", "123", "1234", ..., "123456789"
       
  // and test whether they are prime
       
  std::set<unsigned int> panPrimes;
       
  for (unsigned int digits = 2; digits <= 9; digits++)
       
  {
       
    std::string strNumber = "123456789";
       
    // reduce number of digits
       
    strNumber.erase(digits);
       
 
       
    do
       
    {
       
      unsigned int number = std::stoi(strNumber);
       
 
       
      // test whether pandigital number is prime
       
      bool isPrime = true;
       
      for (auto p : smallPrimes)
       
      {
       
        // abort, no divisors possible
       
        if (p*p > number)
       
          break;
       
 
       
        // divisor found ?
       
        if (number % p == 0)
       
        {
       
          isPrime = false;
       
          break;
       
        }
       
      }
       
 
       
      // found a pandigital prime ?
       
      if (isPrime)
       
        panPrimes.insert(number);
       
    } while (std::next_permutation(strNumber.begin(), strNumber.end()));
       
  }
       
 
       
  // process input
       
  unsigned int tests;
       
  std::cin >> tests;
       
  while (tests--)
       
  {
       
    unsigned int limit;
       
    std::cin >> limit;
       
 
       
    // find next larger pandigital prime number
       
    auto i = panPrimes.upper_bound(limit);
       
 
       
    // smaller than the smallest pandigital prime ?
       
    if (i == panPrimes.begin())
       
    {
       
      std::cout << "-1" << std::endl;
       
      continue;
       
    }
       
 
       
    // upper_bound() goes one step too far
       
    i--;
       
    // and print it
       
    std::cout << *i << std::endl;
       
  }
       
 
       
  return 0;
       
}

This solution contains 13 empty lines, 18 comments and 3 preprocessor commands.