We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime.

What is the largest n-digit pandigital prime that exists?

#include 
     
      #include 
      
       using namespace std;int res = 0;bool prim(int a){	for (int i = 2; i*i <= a; i++)	{		if (a%i == 0)			return false;	}	return true;}void perm(int list[], int n, int k){	int temp1, temp2;	if (n == 1)	{		int sum = 0;		for (int i = k; i > 0; i--)			sum = sum * 10 + list[i];		if (prim(sum)&&sum > res)			res = sum;	}	else	for (int i = 1; i <= n; i++)	{		temp1 = list[i];		list[i] = list[n];		list[n] = temp1;		perm(list, n - 1, k);		temp2 = list[i];		list[i] = list[n];		list[n] = temp2;	}}int main(){	for (int j = 9; j >= 1; j--)	{		int list[200];		for (int i = 1; i <= j; i++)			list[i] = i;		perm(list, j, j);	}	cout << res << endl;	system("pause");	return 0;}