心情那个激动啊~~~~
递推公式是:
a[0]=a[1]=1
a[i]=a[i-1]+2*a[i-2];
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 | import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String[] args) { BigInteger[] res = new BigInteger[255]; res[0] = new BigInteger("1"); res[1] = new BigInteger("1"); for (int i = 2; i <= 250; i++) { res[i] = res[i - 2].add(res[i - 2]); res[i] = res[i].add(res[i - 1]); } Scanner in = new Scanner(System.in); while (in.hasNext()) { int n = in.nextInt(); System.out.println(res[n]); } } } |












or2
咋这么爱激动呢?