\documentclass[]{article}
\usepackage{longtable}
\usepackage{array}
\usepackage{booktabs}
\begin{document}
\begin{longtable}{|m{2cm}||m{1cm}|m{1.5cm}|p{3.8cm}|p{1cm}|p{1cm}|p{2cm}|}
\hline Cubesort & n & $ n \log n $ & $ n \log n $ & n & Yes & Insertion \\
\hline Shell sort & $ n $ & $ n \log^2 n $ or $ n^{3/2} $ & Depends on gap sequence; best known is $ n \log^2 n $ & 1 & No & Insertion \\ \hline
\end{longtable}
\end{document}
But when I add a row just like below, the third row and the the last column cannot centering when I using m:
\documentclass[]{article} \usepackage{longtable} \usepackage{array} \usepackage{booktabs} \begin{document}
\begin{longtable}{|m{2cm}||m{1cm}|m{1.5cm}|p{3.8cm}|p{1cm}|p{1cm}|p{2cm}|}
\hline Cubesort & n & $ n \log n $ & $ n \log n $ & n & Yes & Insertion \\
\hline Shell sort & $ n $ & $ n \log^2 n $ or $ n^{3/2} $ & Depends on gap sequence; best known is $ n \log^2 n $ & 1 & No & Insertion \\
\hline Bogosort & $ n $ & $ n \cdot n! $ & $ \infty $ & 1 & No & Random shuffling \\\hline
\end{longtable}
\end{document}
m
column type and it has two lines.