Small factorials on SPOJ

Question

I am trying to submit my code to the 'Small factorials' problem on SPOJ. It runs successfully on my IDE but shows run time error (NZEC) on SPOJ. Please suggest a solutions.

import java.util.Scanner;
class Factoria
{
    public static void main (String[] args) throws java.lang.Exception
    {
        int t, n;
        int multi = 1;
        Scanner tc = new Scanner(System.in);
        t = tc.nextInt();
        for(int i=0;i<t;i++){
            Scanner nc = new Scanner(System.in);
            n = nc.nextInt();
            for(int f=1;f<=n;f++){
                multi = multi * f;
            }
            System.out.println(multi);
            multi = 1;
        }
    }
}

Answer 1

Your runtime error is likely because you try to initiate a new Scanner on System.in when you already have one open. This seems to fail on Java 8 although seems to run OK on Java 7 - both tested on ideone. There is no need to initiate a new Scanner.

If you simply remove the line

Scanner nc = new Scanner(System.in);

and use tc.nextInt(); instead of nc.nextInt(); it should work.

I note you're doing this for an online competition. You should also note that your factorial will fail (overflow) if the input is > 12 as you're using int type. I don't know whether this will apply in your case.

---

Bugfixed code

import java.util.Scanner;

class Factoria
{
    public static void main (String[] args) throws java.lang.Exception
    {
        int t, n;
        int multi = 1;
        Scanner tc = new Scanner(System.in);
        t = tc.nextInt();
        for(int i=0;i<t;i++){
            n = tc.nextInt();
            for(int f=1;f<=n;f++){
                multi = multi * f;
            }
            System.out.println(multi);
            multi = 1;
        }
    }
}

---

Input

5
4
3
5
2
1

Output

24
6
120
2
1