hdu 1041(规律+打表+java大数)

//规律+打表+java大数

import java.util.Scanner;
import java.math.BigInteger;

public class CT
{
public static void main(String args[])
{
Scanner cin = new Scanner(System.in);
BigInteger []f = new BigInteger[1001];
f[1] = new BigInteger("0");
f[2] = new BigInteger("1");
f[3] = new BigInteger("1");
for (int i=4; i<1001; ++i)
{
if (i % 2 == 0)
{
f[i] = f[i-1].multiply(BigInteger.valueOf(2)).add(BigInteger.ONE);
}
else
{
f[i] = f[i-1].multiply(BigInteger.valueOf(2)).subtract(BigInteger.ONE);
}
}
int n;
while (cin.hasNextInt())
{
n = cin.nextInt();
System.out.println(f
);
}
}
}