uva 10007 Count the Trees

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=948

卡特兰数*n！

 1 import java.math.BigInteger;
 2 import java.util.*;
 3 public class Main {
 4       public static void main(String[]args)
 5       {
 6           Scanner cin=new Scanner(System.in);
 7           BigInteger []a=new BigInteger[1000];
 8           a[0]=BigInteger.valueOf(1);
 9           for(int i=1; i<=300; i++)
10           {
11               int m=(4*i-2);
12               a[i]=a[i-1].multiply(BigInteger.valueOf(m));
13               a[i]=a[i].divide(BigInteger.valueOf(i+1));
14           }
15           int n;
16           while(cin.hasNext())
17           {
18               n=cin.nextInt();
19               if(n==0) break;
20               BigInteger ans=BigInteger.valueOf(1);
21               for(int i=1; i<=n; i++)
22               {
23                   ans=ans.multiply(BigInteger.valueOf(i));
24               }
25               ans=ans.multiply(a[n]);
26               System.out.println(ans);
27           }
28       }
29 }

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