标签：大搬家   1001   

2
1
3

Case #1:
1
Case #2:
4

解题思路： 组合数学相加问题， 还没看懂公式怎么推导的。  先写上：  f(n) = f(n-1) + (n-1)*f(n-2)  

import java.util.Scanner;

public class Main2
{
	public static final int M = 1000000007;
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		long dp[] = new long[1000001];
		dp[1] = 1; dp[2] = 2; dp[3] = 4;
		for (int i = 4; i < dp.length; i++)
		{
            dp[i] = (dp[i-1] + (i-1)*dp[i-2]%M) % M;			
		}
		int T = sc.nextInt();
		for (int cas = 1; cas <= T; cas++)
		{
			int n = sc.nextInt();
		    System.out.println("Case #"+cas+":");
		    System.out.println(dp[n]);
		}
	}
}

1001—大搬家

标签：大搬家   1001   

原文地址：http://blog.csdn.net/first_sight/article/details/45999019