描述标尺长度的递归关系

Recurrence relation that describes the length of a ruler

在之前的数据结构和算法考试中,我被问到以下问题:

   Consider the following sequences of numbers which are the relative lengths of the subdivisions on a ruler. 
   Write a recurrence relation that describes the length of the ruler as a function of n and solve it.
   1 (when n=1)
   121 (when n=2)
   1213121 (when n=3)
   121312141213121 (when n=4)

我输入的答案是:

 T(n)=2^(n)-1

然而,事实证明这是不正确的,我很难想出正确的答案。如果有人能提供一些见解,那就太好了!谢谢!

如果您正在构建字符串本身,您可以这样表达它:

S(n) := S(n-1)nS(n-1) where S(1) := 1

长度相似:

L(n) := L(n-1) + 1 + L(n-1) = 2L(n-1) + 1

递归关系是用前面的术语表示的,这就是为什么你的答案是错误的。

https://courses.engr.illinois.edu/cs573/fa2010/notes/99-recurrences.pdf