hdu 1134 hdu 2067 #Java水卡特兰

1134

import java.io.*;
import java.math.*;
import java.util.*;

public class Main{
	public static void main(String []args){
		Scanner cin = new Scanner(System.in);
		Integer N = 101,i;
		BigInteger []cat = new BigInteger[N];
		
		cat[0] = cat[1] = BigInteger.valueOf(1);
		for(i = 2; i < N; ++i){
			cat[i] = cat[i-1].multiply(BigInteger.valueOf(i*4-2)).divide(BigInteger.valueOf(i+1));
		}
			
		while(cin.hasNext()){
			i = cin.nextInt();
			if(i == -1)
				break;
			System.out.println(cat[i]);
		}
		
	}
}

This is a small but ancient game. You are supposed to write down the numbers 1, 2, 3, ... , 2n - 1, 2n c