blue cup exercises factorial calculation

Don't know what's the problem, the feeling is not wrong thinking, and solve

 
Package Basic_VIP; 

Import the Java. Util. ArrayList; 
import java.util.Scanner; 
Public class Basic_30 {
Public static void main (String [] args) {
Scanner in=new Scanner(System.in); 
Int n=in nextInt (); 
ArrayList Alist=new ArrayList<> (a); 
Alist. Add (1); 
for (int i=1; i<=n; I++) {
Int size=alist. The size (); 
For (int j=0; j//every times I first, and then to carry 
Int temp=alist. Get (j); 
Temp *=I; 
Alist. Set (j, temp); 
} 
For (int m=0; MInt temp1=alist. Get (m); 
If (temp1 & gt; 10) {
Alist. Set (m, temp1%10); 
Int tempResult=temp1/10; 
If (size & lt; {
=m + 1)Alist. Add (tempResult); 
} else {
Int temp2=alist. Get (m + 1); 
Alist. Set (m + 1, + tempResult temp2); 
} 
} else {
Alist. Set (m, temp1); 
} 
} 
} 
For (int I=alist. The size () - 1; i> - 1; I -) {
System. The out. Print (alist. Get (I)); 
} 
} 
}