\documentclass{article}
\usepackage{printsudoku}
\usepackage{solvesudoku}

\begin{document}
\section{Sudoku ausgeben}
\begin{center} 
\sudoku{testsudoku.sud} 
\end{center}

\section{Sudoku loesen}
\sudokusolve{testsudoku.sud}
\end{document} 