3-3 Ordering by asymptotic growth rates
a. Rank the following functions by order of growth; that is, find an arrangement \(g_1, g_2, \ldots , g_{30}\) of the functions \(g_1 = \Omega(g_2), g_2 = \Omega(g_3), \ldots, g_{29} = \Omega(g_{30})\). Partition your list into equivalence classes such that functions \(f(n)\) and \(g(n)\) are in the same class if and only if \(f(n) = \Theta(g(n))\).
\[ \begin{array}{cccccc} \lg(\lg^{^\*}n) \quad & \quad 2^{\lg^\*n} \quad & \quad (\sqrt 2)^{\lg n} \quad & \quad n^2 \quad & \quad n! \quad & \quad (\lg n)! \\\\ (\frac{3}{2})^n \quad & \quad n^3 \quad & \quad \lg^2 n \quad & \quad \lg(n!) \quad & \quad 2^{2^n} \quad & \quad n^{1/\lg n} \\\\ \lg\lg n \quad & \quad \lg^\* n \quad & \quad n\cdot 2^n \quad & \quad n^{\lg\lg n} \quad & \quad \lg n \quad & \quad 1 \\\\ 2^{\lg n} \quad & \quad (\lg n)^{\lg n} \quad & \quad e^n \quad & \quad 4^{\lg n} \quad & \quad (n + 1)! \quad & \quad \sqrt{\lg n} \\\\ \lg^\*(\lg n) \quad & \quad 2^{\sqrt{2\lg n}} \quad & \quad n \quad & \quad 2^n \quad & \quad n\lg n \quad & \quad 2^{2^{n + 1}} \end{array} \]b. Give an example of a single nonnegative function \(f(n)\) such that for all functions \(g_i(n)\) in part (a), \(f(n)\) is neither \(O(g_i(n))\) nor \(\Omega(g_i(n))\).
\[
\begin{array}{ll}
2^{2^{n + 1}} & \\\\
2^{2^n} & \\\\
(n + 1)! & \\\\
n! & \\\\
e^n & \\\\
n\cdot 2^n & \\\\
2^n & \\\\
(3 / 2)^n & \\\\
(\lg n)^{\lg n} = n^{\lg\lg n} & \\\\
(\lg n)! & \\\\
n^3 & \\\\
n^2 = 4^{\lg n} & \\\\
n\lg n \text{ and } \lg(n!) & \\\\
n = 2^{\lg n} & \\\\
(\sqrt 2)^{\lg n}(= \sqrt n) & \\\\
2^{\sqrt{2\lg n}} & \\\\
\lg^2 n & \\\\
\ln n & \\\\
\sqrt{\lg n} & \\\\
\ln\ln n & \\\\
2^{\lg^\*n} & \\\\
\lg^\*n \text{ and } \lg^\*(\lg n) & \\\\
\lg(\lg^\*n) & \\\\
n^{1 / \lg n}(= 2) \text{ and } 1 &
\end{array}
\]
b. For example,
\[
f(n) =
\begin{cases} 2^{2^{n + 2}} & \text{if $n$ is even}, \\\\
0 & \text{if $n$ is odd}.
\end{cases}
\]
for all functions \(g_i(n)\) in part (a), \(f(n)\) is neither \(O(g_i(n))\) nor \(\Omega(g_i(n))\).
本页面的全部内容在 小熊老师 - 莆田青少年编程俱乐部 0594codes.cn 协议之条款下提供,附加条款亦可能应用