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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