Problem Description
人称“AC女之杀手”的超级偶像LELE最近忽然玩起了深沉,这可急坏了众多“Cole”(LELE的粉丝,即"可乐"),经过多方打探,某资深Cole终于知道了原因,原来,LELE最近研究起了著名的RPG难题:
有排成一行的n个方格,用红(Red)、粉(Pink)、绿(Green)三色涂每个格子,每格涂一色,要求任何相邻的方格不能同色,且首尾两格也不同色.求全部的满足要求的涂法. 以上就是著名的RPG难题. 如果你是Cole,我想你一定会想尽办法帮助LELE解决这个问题的;如果不是,看在众多漂亮的痛不欲生的Cole女的面子上,你也不会袖手旁观吧? |
Input
输入数据包含多个测试实例,每个测试实例占一行,由一个整数N组成,(0<n<=50)。
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Output
对于每个测试实例,请输出全部的满足要求的涂法,每个实例的输出占一行。
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Sample Input
1 2 |
Sample Output
3 6 |
Code
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Key Points
for f(n) n>3, there are two conditions.
this is f(n-1), because this condition is same as f(n-1)
this is 2*f(n-2), because the if the last second color is same to the first one, the last third color can't be same to the first one. Consequently, it's f(n-2), and you will find the the last one color have two cases, so, it's 2*f(n-2). |
![](https://img2024.cnblogs.com/blog/35695/202408/35695-20240826070647288-243310440.jpg)