Blog of RuSun

\begin {array}{c} \mathfrak {One Problem Is Difficult} \\\\ \mathfrak {Because You Don't Know} \\\\ \mathfrak {Why It Is Diffucult} \end {array}

主定理

$$
If \quad T(n) = aT(\left \lceil \frac{n}{b} \right \rceil ) + O(n ^ d),
$$

$$
then:T(n) = \begin{cases}O(n ^ d) \quad if \quad d > \log_{b}{a}
\\O(n ^ d \log n) \quad if \quad d = \log_{b}{a}
\\O(n ^ {\log_{b}{a}}) \quad if \quad d < \log_{b}{a}
\end{cases}
$$