hdu 1131 Count the Trees

卡特兰数*阶乘就是答案     第一次用java。。高精度写起来好快。。。。不过代码比较丑。。

import java.math.BigInteger;

import java.util.Scanner;

  

public class Main

{  

    public static void main(String []args)

    {  

        Scanner cin = new Scanner(System.in);  

        int i,ii;

        BigInteger []c= new BigInteger[105];

        BigInteger []jie= new BigInteger[105];

        BigInteger linshi2;

        c[0]=new BigInteger("1");

        for(i=1;i<=100;i++)

        {

            int u=4*i+2;

            String str=String.valueOf(u);

            BigInteger ww=new BigInteger(str);

            linshi2=c[i-1].multiply(ww);

            u=i+2;

            String strr=String.valueOf(u);

            BigInteger www=new BigInteger(strr);

            c[i]=linshi2.divide(www);

        } 

        jie[1]=new BigInteger("1");

        for(ii=2;ii<=100;ii++)

        {

            int ef=ii;

            String trt=String.valueOf(ef);

            BigInteger rr=new BigInteger(trt);

            jie[ii]=rr.multiply(jie[ii-1]);

        }

        while(cin.hasNext())

        {

            int pp=cin.nextInt();

            if(pp==0) break;     

            System.out.println(c[pp-1].multiply(jie[pp]));

        }

    }  

}