Q:

Trouble with table layout

Hello fellows and folks!
I need to get what's on the picture:

I'm not very good when it comes to multirows. This is what I have tried so far:
\documentclass{article}
\usepackage{caption}
\usepackage{adjustbox}
\usepackage{setspace}

\usepackage[margin=1in]{geometry}
\usepackage{multirow,tabularx}
\renewcommand{\tabularxcolumn}[1]{m{#1}}
\newcolumntype{Y}{>{\centering\arraybackslash}X}
\renewcommand{\arraystretch}{2}
\begin{document}\pagestyle{empty}

\begin{table}
    \parbox{1\linewidth}{
        \centering

    \begin{tabular}{|l|l|l|}
        \hline
    \textbf{Dataset}    &\textbf{ Method }&\textbf{ Best Hyperparameters } \\ \hline
    100K    & BSVD Bias & $k=50$, $\gamma =0.01$, $\lambda=0.1$  \\\hline
    1M  & BSVD Bias & $k=50$, $\gamma =0.01$, $\lambda=0.1$\\ \hline
    \end{tabular}

\caption{Foo}
}
\parbox{1\linewidth}{
    \centering
    \begin{tabular}{|l|l|l|}
        \hline
        \textbf{Dataset}    &\textbf{ Method }&\textbf{ Aerage RMSE } \\ \hline
        100K    & BSVD Bias &  $0.9175$  \\\hline
        1M  & BSVD Bias & $0.8620$ \\ \hline
    \end{tabular}

\caption{Bar}

\end{table}
\end{document}

Which yield:

A:

Example 1
I leave it to you to fill in the correct data where I put the Xs. You should also consider to use less arraystrech, remove vertical lines and use booktabs, see my second example:
\documentclass{article}
\usepackage{caption}
\usepackage{adjustbox}
\usepackage{setspace}

\usepackage[margin=1in]{geometry}
\usepackage{multirow,tabularx}
\renewcommand{\tabularxcolumn}[1]{m{#1}}
\newcolumntype{Y}{>{\centering\arraybackslash}X}
\renewcommand{\arraystretch}{2}
\begin{document}\pagestyle{empty}

\begin{table}
\centering

\begin{tabular}{|l|l|l|}
\hline
\textbf{Dataset}      &\textbf{ Method }&\textbf{Best Hyperparameters}           \\\hline
\multirow{2}{*}{100K} & BSVD Bias       & $k=50$, $\gamma =0.01$, $\lambda=0.1$  \\\cline{2-3}
                      & Proposed Method & X                                      \\\hline
\multirow{2}{*}{1M}   & BSVD Bias       & $k=50$, $\gamma =0.01$, $\lambda=0.1$  \\\cline{2-3}
                      & Proposed Method & X                                      \\\hline
\end{tabular}
\caption{Foo}

\centering
\begin{tabular}{|l|l|l|}
\hline
\textbf{Dataset}      &\textbf{Method}  & \textbf{Aerage RMSE} \\\hline
\multirow{2}{*}{100K} & BSVD Bias       & $0.9175$             \\\cline{2-3}
                      & Proposed Method & X                    \\\hline
\multirow{2}{*}{1M}   & BSVD Bias       & $0.8620$             \\\cline{2-3}
                      & Proposed Method & X                    \\\hline

\end{tabular}
\caption{Bar}
\end{table}
\end{document}

Example 2
\documentclass{article}
\usepackage{caption}
\usepackage{adjustbox}
\usepackage{setspace}

\usepackage[margin=1in]{geometry}
\usepackage{multirow,tabularx, booktabs}
\renewcommand{\tabularxcolumn}[1]{m{#1}}
\newcolumntype{Y}{>{\centering\arraybackslash}X}
\renewcommand{\arraystretch}{1.2}

\begin{document}\pagestyle{empty}

\begin{table}

        \centering

\begin{tabular}{@{}lll@{}}
\toprule
\textbf{Dataset}    &\textbf{Method }&\textbf{Best Hyperparameters } \\ \midrule
\multirow{2}{*}{100K}    & BSVD Bias & $k=50$, $\gamma =0.01$, $\lambda=0.1$  \\\cmidrule{2-3}
                & Proposed Method   &   X\\\midrule
\multirow{2}{*}{1M}  & BSVD Bias & $k=50$, $\gamma =0.01$, $\lambda=0.1$\\\cmidrule{2-3}
                & Proposed Method   &   X\\
\bottomrule
\end{tabular}

\caption{Foo}

\medskip

\centering
\begin{tabular}{@{}lll@{}}
\toprule
        \textbf{Dataset}    &\textbf{Method }&\textbf{Aerage RMSE} \\ \midrule
        \multirow{2}{*}{100K}    & BSVD Bias            &   $0.9175$  \\\cmidrule{2-3}
                & Proposed Method   &   X \\\midrule
        \multirow{2}{*}{1M}     & BSVD Bias             &   $0.8620$ \\\cmidrule{2-3}
                & Proposed Method   &   X\\
\bottomrule

    \end{tabular}

\caption{Bar}

\end{table}
\end{document}

