Foj 1147 Tiling

Accept: 233    Submit: 575
Time Limit: 1000 mSec    Memory Limit : 32768 KB

 Problem Description

In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles?

Here is a sample tiling of a 2x17 rectangle.

 

 

 Input

Input is a sequence of lines, each line containing an integer number 0 <= n <= 250.

 Output

For each line of input, output one integer number in a separate line giving the number of possible tilings of a 2xn rectangle.

 Sample Input

2

8

12

Sample Output

3

171

2731

big[i]=big[i-1]+big[i-2]*2

菜鸟的做法, java.....

import java.math.BigInteger; import java.util.*; public class Main { static BigInteger[] big = new BigInteger[251]; public static void main(String[] args) { init(); Scanner in = new Scanner(System.in); int n; while(in.hasNext()) { n=in.nextInt(); System.out.println(big[n]); } } public static void init() { big[0]=new BigInteger("1"); big[1]=new BigInteger("1"); big[2]=new BigInteger("3"); for(int i=3;i<=250;i++) big[i]=big[i-1].add(big[i-2].multiply(new BigInteger("2"))); } }